PLEASE HELP!!!! ((SFW))

Hi, I'm a young slightly plus sized woman and I've been healthy physically all of my life. A few days ago, I woke up with a dark purple bruise-like spot on my upper right breast. It hasn't changed from the size of my pinky nail. It feels slightly raised, but there's no pain. It started to fade off a while ago, like my body was clearing a blood clot. But it recently went from bruise purple to a red color. I do have a bigger chest, so maybe that would affect it? Over all, I just need more direct answers than Google searches. Just seeing pages worth of inflammatory breast cancer stuff makes me so anxious and distressed. I only have one, and I have all of my normal bumps and stuff (bigger chest; cystic fibromyalgia).

Other places where women would post about them come up with no direct responses, just what they did to find out. I'll put a picture as well for reference. (after it turned red)

UPDATE: Thank you all so much for helping!! I have all the necessary materials to take care of it now. <3