Sorry to hear you are in pain, it adds to all of our worries on top of everything else!
I don’t have skin mets or know that much about them but when I was having chemo a few years ago (for mets) the lady next to me had skin mets on her breast. She was having chemo to shrink them, she had no other mets at all. The chemo shrunk them to a tiny dot that never quite went away. Chemo may be an option for you rather than surgery? Or in addition to surgery if a mastectomy is also needed ?
I'm not sure at the moment if anyone on the forum has skin mets, they don’t appear to be such a common site for mets as the others such as bones, liver, lungs. You may not get many replies in that case as we all tend to answer about what we know about and can help with. Im not sure where else you can find out more info which is frustrating if you’d like a bit more advice. The helpline on this website might help or point you in the right direction.
Good luck and do come back on here for support or any other questions you might have.