Hello, im 20 year old woman never had sexual intercourse but a week ago, i had my first oral sex with my boyfriend when he visited. i swallowed his semen when he ejaculated into my mouth and after that, i got rashes or hives on my lower part of my back (right above my butt) and my belly area. my boyfriend told me he had a STD check already and doesn't have any transmitted diseases. its been almost a week and my skin irritation is getting worse. i am scared. is it possible for me to have sexually transmitted disease even if i didn't have any sexual intercourse or is this semen allergy?