Suggest Treatment For Itchy Rashes All Over After Taking Bactrim

I just realized that I'm having a reaction to the Bactrim my DR prescribed for the boil i had taken care of on Wednesday. I've never had any problems with Bactrim before, but I had Gastric Bypass 5 weeks ago. I guess that changes things. I have small itchy rashes popping up all over my body. I'm definitely going to stop taking it.. what should be my next step?