My 13-yr.old son has a slight enlargement of his left nipple. The nipple itself is not flat like his right one. He has no pain, no tenderness, no discharge, no change in color. When pressing on his breast, it felt slightly hard, lumpy, compared to his other one.
Due to an eye injury at the end of May, he went for steroid injections for a few days and then prednisone for about five days after his surgery. I'm wondering if this change in his breast/nipple is due to that or puberty.