I'm not sure what new medication you've been taking, but the if the rash popped up at the same time then there could be a correlation. You'll probably have to either do a swab or blood test (for herpes) or see what happens when (if) you stop your medication.
As far as Herpes, it can look like anything. Mine just appears as a few bumps, no blisters or anything, just a rash that I didn't think much of for a few years until I started getting suspicious. I get it on my bum... it can be anywhere. It seems to take so many different forms on different people it's mind boggling! I'd say look into the possible side effects of whatever medication you've been taking and maybe talk to your doctor and see what he/she thinks. If it is Herpes, you'll find tons of wonderful support and advice on this board.
Good luck!