Hi I've Been Getting A Rash Every Time I'm In

Hi I've been getting a rash every time I'm in the sun. It isn't itchy but is red and blotchy. I had it two months ago for 2 weeks but it cleared and skin was completely normal. About three weeks ago it came back and I'm really stressed about it. I am often allergic to penicillin drugs which I had a round of them about a month and a half ago and I usually get a rash from it but I'm worried its hiv.