I just wanted to respond because I too have had a flat pink patch that is not itchy on my chest and I have had it for almost 8 years. It "arrived" after my bc surgery and scared the wits out of me. Like you, everyone who saw it said the same thing - not skin mets. I almost was going to just have a biopsy but finally a new onc also said - this is not skin mets. So, I watched it and I still watch it (I still HAVE it). I guess its part of the new me. It has not changed in size, color, shape. It's just there and obviously wasn't cancer or I'd have certainly known by now. I always showed it to every doctor I needed to go to - not just the cancer docs (and no - I didn't show it to the dentist, eye doctor or vet
).
So your story sounds like mine - I watched it forever just to say "I told you so" but it just didn't happen. So trust (but check it now and again). And keep asking. I did. It helps to hear, "its not skin mets".