Talk to Dermatologist on Skin Problem

23,F, Unmarried, Regular Menstrual Cycle, No underlying health issue.

Respected Doctor, I have this region of white/discolored strip in the region between my nose and lips. It has been like this for more than a year. Maybe not too visible in the picture, but it is very prominent especially post-exertion. I had it checked by a dermatologist who recommended Cilix cream for a month and then MelaCare + HiTone creams for another. But there has been no change. Is this a skin issue or related to something else? This problem has become a huge insecurity for me as it is very prominent and makes my upper lip region look flushed. Any help would be greatly appreciated. Thank you.