Girls, I need advice?

So I’m a teen and for a couple years (ever since puberty) I’ve had this discoloured spot underneath my breast

it kinda hurts when it’s touched and I never thought anything about it until now. it’s not a pimple or anything like that, it kinda looks like a birthmark but it’s not. Someone please give me your thoughts and opinions it would really help

Girls, I need advice?
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