I had this as a kid and hated it cause I had to take my shirt off in gym class once in a while and kids stared. Doc told me I had to have surgury to remove the tissue since I was born with it. I just dealt with it and still have it to this day.
If it is tissue then yea I will opt for surgery. I can feel a lump sometimes. So I'm guessing it is a hormonal issue. I work so damn much sort of make it hard to go see the doc. But have to make an effort to go next week
Maybe follicuitis or eczema from shirt irrtation, is often infected by a bacterium called Staphylococcus aureus, which makes the skin worse and slower to heal.
Try tipile antiboitic neomycin cream or hydrocortisone. Prolactin tumor is a slim possobility, and we would suspect a dopamine depression.