What's wrong with my lip? I had hyaluronic acid filler 1 year ago

Hi and thank you for your question!
It is difficult to tell by a picture alone, but it is unlikely that a filler placed 1 year ago will give you swelling of your lips like that. (Skin necrosis by the way, happens immediately after injecting lip filler, so no need to worry about that). It is more likely you are having an allergic reaction to something that you ate or touched your lips. If it happens again, I would consult a physician who specialized in allergy and immunology. I have seen cases where filler lasts longer than a year and migrates, and hyaluronidase dissolves that filler well.
So- if the swelling is temporary, it is likely an allergic reaction that has passed, and if it happens again, you should consult an allergist. If it is constant, then it is possible (although still uncommon) that it is due to filler, and in that case, hyaluronidase injection may be used to resolve it in that situation.
Best of luck,Brandon Elnekaveh, MD

For unique cases where a variety of modalities could be used to treat the condition, I would suggest an in-person or virtual consultation to develop a custom and effective treatment plan. It is difficult to precisely define the best option without collecting the same information. I suggest reaching out to an expert for a consultation with surgical and non-surgical methods to get a comprehensive option. Best, Dr. Emer.

This is also not a cold sore. What is going on here is the progressive break down of hyaluronic acid filler. This causes the filler to hold more water relative to the remaining filler. This causes the lip to actually look more full than it did when first treatment. Filler migration can also contribute to this. Generally filler treatment hold up for 6 to 12 months. At the end of 12 months, generally there is plenty of filler that remains. The overall clinical effect is often not as magical as it was when first placed. For some, this means topping off the service. For others, the effect of filler break down warrants the removal of the prior service and a fresh hyaluronic acid filler treatment. This later approach is what I would recommend for you. Generally, the old filler should be removed and a new service not placed for about a week. I do believe that your upper lip was over-treated and would counsel you to have less upper lip volume in the future.