I have this patch on my skin about an inch large near my mouth and cheek. It is bumpy and slightly dark. The patch has been there all my life, but it doesn't irritate me at all. It behaves like normal healthy skin, but doesn't look like it. A doctor once used this thing to freeze it, and the patch flaked off after a week or 2, but i'm not sure what he used. My skin later recovered slightly lighter, then back to its usual defectiveness. I really need to know what he used, can somebody please help me identify it? Thanks