Thanks for the quick response!
I am 35 years old, and have been wearing underwires for as long as I can really remember. This indentation and discoloration is new however. It looks like an old bruise that is kind of dry. I am black (medium skin tone) and the discoloration is a dark brown.
There is not a lump that I can feel, but the dimple remains there with my arms up, down, standing or lying down??? There also isn't any pain, if it werent for the dark color, I probably wouldn't have noticed it at all.
I have marks under my breasts from the wire in the bra, but this dimple is in the far outside of my breast area (imagine right underneath your arm at breast level)
Hopefully this answers your questions??