I’ve always considered myself a Heterosexual male attracted to women but I recently had my first encounter with a male. I gave the male a brief unprotected blowjob. By brief I mean like 6-10 seconds long before I realized I didn’t care for doing that kind of thing. The male did NOT ejaculate in my mouth but there was pre cum. I’m unsure if his HIV status as I did not ask and it was a spur of the moment thing. Well afterwards I realized I had a small canker sore/ulcer smaller than a grain of rice on the inside of my bottom lip. I’m terrified that HIV could have been transmitted through this small sore? What would you say my chance at infection is? I’m fully aware other STDs are possible but I’m terrified about HIV specifically. I did not get PEP due to reading that it most likely wouldn’t be prescribed for being a low risk exposure. When is the earliest I could get tested and would you recommend it? I’m freaking out. Thank you for taking time to read this. 

This was a much less risky event than you seem to fear. With such a brief oral exposure, and without ejaculation in your mouth, the chance you were infected was near zero even if he had a urethral STD like gonorrhea, chlamydia, etc -- and even lower if you did not observe any abnormal discharge, mucus, etc. As for HIV, there are very few infection ever believed to have been acquired by oral sex. One risk estimate by CDC, based on how people thought they acquired HIV (which often is mistaken), is one chance in 10,000 if the penile partner has untreated HIV. And that's with ejaculation in the mouth. It is equivalent to giving BJs to completion to HIV infected men once daily for 27 year before catching HIV would be likely. Could having a canker sore at the time elevate the risk? I suppose so -- but canker sores and other oral health problems are pretty common, so there must have been billions of exposures in their presence --and still very few known cases of HIV transmission. 

The risks for other STDs is almost as low. I mentioned gonorrhea and chlamydia above. There is also little or no risk for HPV, herpes, or anything else.

I would advise against no STD testing at all. In any case, however, a blood test two days after exposure is meaningless. No STD can give positive blood test results sooner than a few weeks after exposure; and there are no accurate blood tests for gonorrhea or chlamydia. The only valid testing for them requires specimens from the exposed site(s) -- in your case, a throat swab. But really, you don't even need that.

My final advice is psychological, which really isn't my strength. But don't confuse your apparent anxieties over a sexual choice you regret with infection risk from the event. They aren't the same.

I hope these comments are helpful and you can relax a bit. This was really a non event in terms of HIV and STI risk.

HHH, MD

That concludes this thread. Thanks for your kind comments. Best wishes and stay safe.