Possible bone Mets collarbone

Hi all - I was originally diagnosed in 2010 with stage 1 IDC. Had lumpectomy, radiation, and tamoxifen. All was well then a few weeks ago this pimple-like growth appeared on my collarbone. I wasn’t really worried until this weekend when I noticed an area the size of a half dollar was swollen and the collarbone itself seems much larger than the other side. Saw the oncology NP today. She’s pretty confident that it’s not a lymph node but she consulted with the oncologist and now I have to have a bone scan. She wasn’t at all concerned about the little skin thing but the collarbone itself is definitely larger than it was (a lot larger than the other side). It doesn’t hurt at all. I’m trying to be optimistic but I’m worried. They got me scheduled quickly for the bone scan (this Saturday). I would appreciate any words of wisdom