I had a TKR on 2/7 and have subsequently broken out into Prickly Heat. It started as a rash but quickly became more than that. It's all over my stomach, back and lower back into the buttocks. I haven't had my first post-op appt yet so there's no one to ask. Very painful, it "weeps" and spreads and is an unwelcome addition to the pain family. Some said to take Benedryl but I'm worried about Benedryl along with the oxycodone. And one had advice for me?