spots

I had my monthly Her2 treatment and about four days later i have res spots on my upper arm?? I have been on treatment for over a year, is this normal?? Can skin mets show up that fast??

Hi -
Hope it is not skin mets. But if it persists, get it checked by someone.
There are any number of reasons to get a rash. Have you been working in your garden? Eaten new foods, worn a clothing item made from some new-to-you fabric? Used a different soap?
I never had a rash from my Herceptin, but get them from time to time due to allergies or sensitivities.