How To Get Rid Of Hive Like Rash All Over The Body?

I had strep throat about a month and a half ago. The doctor prescribed me cephalexin even though I am allergic to penicillan. I broke out in a hive like rash all over my body and was put on steroids to get rid of it. It cleared up a lot but didn't go away completely. It has been a month now and it is still there. It gets worse when I get cold or after I take a hot shower. Will it ever go away?