In short
- The swelling of the first few weeks is not migration. It is the response to the injection itself, and judging the result before it settles leads you astray.
- Filler lasts longer than people think. A retrospective study of the tear trough described significant improvement up to 18 months, well beyond the 6 to 12 that are assumed by default.
- That figure changes the reasoning: “it must have gone by now” is usually false, and what you can see may still be product.
- A late inflammatory reaction is another matter altogether: it usually appears between three and four months and it has causes and management of its own.
- None of this is decided in the mirror. What separates one situation from another is the examination and the history: which product, how much, where and when.
- If there is increasing pain, a change of colour or any disturbance of vision, this is not it: that is an emergency and it has a page of its own.
“My filler has migrated” is now one of the sentences most often repeated in consultation, and in a good many cases what is in front of you is not migration. It may be swelling, which is the normal response to an injection and takes longer to go than people expect. It may be product still exactly where it was put, which has not gone because filler lasts considerably longer than is supposed. And sometimes it really is product that has shifted.
All three look similar in the mirror and they are treated differently, so confusing them leads to the wrong decisions: dissolving something that was only swollen, or waiting for something to go on its own that is not going to.
This page sets out a frequent question about hyaluronic acid treatments. If what you notice is a localised lump or an asymmetry, the page that applies to you is lumps and asymmetry after a filler.
Three things that look alike and are not the same
- Swelling. It appears from the outset, it is diffuse rather than localised, it usually affects the whole area treated and it gradually settles. It is the expected response to the needle and to the product itself, which draws in water.
- Product still where it was put. Nothing has moved: the filler is simply still there longer than the patient expected, and as the face around it changes it can start to show where it used to go unnoticed.
- Migration. The product occupies a different territory from the one it was placed in: beyond the border of the lip, for instance, or above the groove it was put in. It is felt as a ridge or a swelling outside the contour that was treated, and it is usually more stable over time than swelling.
The figure that changes the reasoning
Almost everyone assumes that a filler lasts between six months and a year. That assumption is the source of half the confusion, because if fourteen months have gone by the automatic conclusion is “this cannot still be the filler”.
A retrospective study of hyaluronic acid filler in the tear trough found significant improvement of the infraorbital hollow up to 18 months after treatment, a period the authors themselves flag as longer than the duration usually assumed.
The practical reading is twofold:
- If you notice something odd and months have gone by, ruling the filler out on the calendar is a mistake. It may still be there.
- And the other way round: that same thing explains why a result that looked right at first can look different over time, without anyone having injected anything again.
When the swelling appears late
There is a scenario that does not fit any of the three categories above and is worth knowing about: the late inflammatory reaction.
The consensus published in 2024 on late reactions to hyaluronic acid places them usually between three and four months after the injection, although occasionally they appear much earlier. It proposes three possible causes: the physicochemical characteristics of the product, an infection or biofilm, and an immune imbalance in the patient —an autoimmune disease, a recent viral infection.
It matters because the management is not the same: that consensus reserves hyaluronidase for non-inflammatory reactions without active infection, proposes observation or a steroid in inflammatory ones, and in infectious ones indicates drainage, culture and antibiotics. It is set out in full on the hyaluronidase page.
How this is genuinely assessed
There is no magic test. What makes the difference is information and examination:
- What was injected, how much and where. Everything you remember about the previous treatment counts: which product it was, in which area and how much. It is the information that saves the most time.
- When. The time elapsed points towards early swelling, persistent product or a late reaction.
- How it behaves. It is palpated: whether it is soft and diffuse, whether it is firm and well defined, whether it hurts, whether it changes with position or through the day.
- Whether there are inflammatory signs: redness, heat, pain. They completely change what is done.
- What has changed since then. Whether it has grown, whether it has shifted or whether it has been the same for months. It is what distinguishes “it has moved” from “it was always like that and now you have noticed”.
What does not help
- Massaging it yourself. Unless expressly told to by whoever treated you, no.
- Dissolving it blind. If what there is is swelling, hyaluronidase will not take it away, and it can undo product that was correctly placed.
- Putting more filler on top to compensate. It usually makes the underlying problem worse.
- Judging the result in the first week. It is when the area is at its most swollen and least like the final result.
When not to wait
This page is about an aesthetic problem, not an emergency. But the limit is worth being clear about: pain that is increasing, pallor or a change in the colour of the skin, or any disturbance of vision are not migration or swelling. They call for immediate attention and they are described on the vascular occlusion page.
Book an appointment
You can book your own appointment. Pick the day and time from the free slots in the diary, in a panel that opens right here, without leaving this page.
Frequently asked questions
How do I know whether my filler has moved?
By where it is, not by how it looks. Migration occupies a different territory from the one that was treated —outside the border of the lip, for example—, whereas swelling affects the whole area and settles with time. It is confirmed by examination, not in the mirror.
I had filler more than a year ago — can it still be there?
Yes, and it is commoner than people think. A retrospective study of the tear trough described significant improvement up to 18 months, beyond the duration usually assumed.
Is the swelling of the first few days normal?
Yes. Swelling after an injection is to be expected, and that is why the result is not judged in the first week.
My lips are swollen above the border — is that migration?
It is the pattern most associated with migration, but it can also be accumulated product or swelling. Before dissolving it is worth having it assessed, because what is done changes.
Can it be prevented?
The product chosen, the amount, the plane it is placed in and the area all play a part. There is no guarantee, but the technical choices count.
If it is migration, can it be taken away?
Hyaluronic acid is reversible with hyaluronidase. Whether that is what is indicated depends on exactly what is there and on whether there are signs of inflammation or infection.
And if I had it done at another clinic?
It is assessed just the same, during consulting hours. What helps most is your knowing which product you were given, in which area and when.
Could it be a late reaction?
It could. They usually appear between three and four months, and their management is different from that of simple migration: which is why it is assessed before being treated.
Sources
- Puyana C, Montes JR. Long-Term Effects of Tear Trough Hyaluronic Acid Filler: A Retrospective Study. J Clin Aesthet Dermatol. 2025. It describes significant improvement of the infraorbital hollow up to 18 months after treatment, beyond the 6 to 12 months usually assumed. https://pubmed.ncbi.nlm.nih.gov/41446717/
- Baranska-Rybak W, Lajo-Plaza JV, Walker L, Alizadeh N. Late-Onset Reactions after Hyaluronic Acid Dermal Fillers: A Consensus Recommendation on Etiology, Prevention and Management. Dermatol Ther. 2024;14(7). Late reactions usually between 3 and 4 months; three aetiological hypotheses; differentiated management according to whether they are non-inflammatory, inflammatory or infectious. https://pubmed.ncbi.nlm.nih.gov/38907876/
- Murray G, Convery C, Walker L, Davies E. Guideline for the Management of Hyaluronic Acid Filler-induced Vascular Occlusion. J Clin Aesthet Dermatol. 2021. https://pubmed.ncbi.nlm.nih.gov/34188752/
Book your consultation
If you have spent some time thinking your filler has moved and do not know whether to wait or to have it taken out, that question is settled by examining: the area is palpated, which product was put in and when is reviewed, and you are told whether what is there is swelling, product in its place or product that has shifted —and whether anything should be done or nothing at all.
We also assess people who were injected somewhere else, during consulting hours.
Clinical confirmation by the surgeon
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Last reviewed: 23 August 2026. This content is for information only and does not replace an individual assessment by a healthcare professional.
