So I'm going to up front a bleak, 2 nights ago me and my girlfriend had rough sex, she was just ending her period, but we had sex and it was rough, and we used a condom. The morning after that, I found red rashes and common pimples around my penis. Now, today, the pimples spread a little and so did the rash. Please tell me its just friction burn or something. Anything but an STD. Neither me nor my girlfriend have an STD. HELP!