HI, I AM SUFFERING WITH A BREAK OUT ON MY

hI, i AM SUFFERING WITH A BREAK OUT ON MY ARM, i HAVE THOUGHT IT WAS POISON iVY SINCE I had been weeding a shrub. I've been using Ivarest ointment OTC, for about 3 days. It is still spreading and blistery. I have had a shingle vac, and I'm wondering if it could possibly be shingles. I'm having surgery a week from today and am worried that this might be a problem or even a danger, Do I need to see Dr. or just keep treating and hope it dries up in a week?