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

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.

Your lip swelling is unlikely to be related to your lip fillers over a year ago.
Since your symptoms have resolved I think you can probably put this behind you.
If it happens again contact your primary care doctor and consider asking for a referral to an allergist.
Best,
Mats Hagstrom MD