rash on right side of right breast

Hi all, I am 12 years recovered from MI-DCIS HER2+. I had a bilateral mastectomy and I had reconstruction one year later. I am just getting out of the shower and while drying off in the mirror I noticed a rash on the right side of my right reconstructed breast. I seem to get a little freaked out every time I see something different, and I know that most of the time it is something benign. I guess I am just wondering if anyone has experienced anything like this?

I feel like I should add that I visited my gp last week and she noticed a node under my chin was swollen. I mean, I know that the chin is a little far from my breast but...

Someone please offer me some guidance and help me know everything is okay.

I hope this offers some explanation. About four years after my first mastectomy, I noticed the outside of my breast showed red rash. It didn't cause any sensation except maybe a little itchy. The oncologist suspected thyroid deficiency but the test result was negative. As time went on, it spread and looked darker. The skin felt a bit more rough than normal. When I went for the second opinion (for my second breast cancer), the resident seemed to be alarmed by them but the breast surgeon wasn't concerned. I decided to put heavy moisturizer and see if that makes any difference. Now the marks have largely fainted. My theory is that the foobs are still moving and morphing years after surgery. Somehow one became irritated by the bras even though they were carefully fit in the first place.