How to reverse fat transfer to lip almost 20 years later? And hyaluronic filler 9 years later? (photos)

HA filler can be reversed with hyaluronidase. It may take a series of treatments. A combination of 5/FU steroids, lasers, microneedling/prp and radiofrequency can give improvement if you're unhappy with your fat transfer. I recommend getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer

It seems at this point, it is more likely to be the fat causing this problem. To my knowledge the only way to fix this problem is to extract some of the fat through small incisions on the underside of the lip.  Filler most likely would be resolved by now.

I agree there is some unevenness of your upper lip. Most likely, it is the fat that is causing the areas of fullness. It is very unlikely the filler is still there and causing any issues. You would need an in person evaluation to feel the lip and recommend treatment. You may need removal of small amounts of fat with very small incisions in the lip. You might also need a small strip of the inner aspect of the upper lip to remove the "underside" that shows with smiling.
Thank you for your question and best wishes on getting your issue resolved.