I perform oral sex with a stranger, I shouldn't have had but what done is done, i couldnt turn back time and I feel guilty and regret and scared. I accidentally biten my lips a week before I have oral sex for him. He cum a teaspoon of cum into my mouth and I quickly spitt it out, and I am sure that his cum touches my visible ulcer which were healing in process that time,which is no longer painful like the first time but its still visible. If he have std, will I get infected? I am very worry now and I couldn't sleep. Please help me...and I was currently eating doxycycline for my acne, wil doxycycline kill the std at the same time?/