I have a dark line right between my breasts on my breast line. It doesn't itch. It's not dry. It's perfectly normal feeling and looking skin other than the color. However, I am self conscious about it. I mentioned it to my dermatologist and he told me to scrub it. It's not dead skin. I've scrubbed and exfoliated to the point where it hurt. Is there any way to get rid of the discoloration?