How do I fix the discoloration on my bottom lip? (Photo)

This can be improved with lasers, microneedling/prp and medical tattooing. I recommend getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer

Thank you for your question. I suggest that you move forward and consult with a board certified facial plastic surgeon.
Best wishes,

There is no dependable method of stimulating natural pigment in exact location although on occasion one can see improvement overtime after repetitive micro needling that covers both: the area with pigment deficiency and the normal pigment area. Your best and least expensive bet is tattoo. Any degree of improvement will give you great results. Good luck!