What Kind of Procedure and How Much Would It Cost for Me to Have Lip Scar Tissue Removed?

I was in a playground accident as a child that left me with stitches in my upper right lip. The scar healed with extra tissue mainly on the inside of my lip. I have always been extremely self conscious of the "bump" (the actual scar doesn't bother me as much as the extra tissue does) and now that I am older am interested in finding out what I can do about it, and approximately how much it would cost to have it fixed. Many thanks!