please help with skin mets question

[CherylS]

Over the past week or so I have developed a rash under my surgery arm. It is about an inch above the incision where my sentinal node biopsy incision is, when I lift my arm. There are red bumps, two have become pretty noticeable and kind of hard over the past day. The whole area itches. I wad dx at stage 1, but I know anything can happen. Any help from my panel of experts here?