Thanks for your great service. My long-term relationship recently ended and did something stupid while depressed. Yesterday I felt a spot at the very top of my mouth. It seemed to fall off and 4 hours later, in my stupidity, i went to a transsexual escort. I performed oral sex on her and she ejaculated in my mouth. When i got home, and the following day, i realised there was still some discomfort at the top of my mouth and now i fear there may have been a wound there (after the spot fell off) and the semen may have come into contact with it. Of course, i will get tested for this but what is my risk?

Thank you for your help!

I have no idea how to interpret the "spot" in your mouth, but I see no reason that it would change the HIV/STD risk in this situation. From an HIV perspective, there really shouldn't be any worry. Even if she has untreated HIV, the estimated transmission risk from this even would be 1 in 10,000. That's equivalent to doing the same with infected partners once daily for 27 years before you were infected. And of course you don't know she has HIV -- probably not. As for other STDs, the risk is higher, mostly for gonorrhea or syphilis. But still unlikely for any single event.

Therefore, testing is optional. Feel free to do it if you wish. If so, have a throat swab for gonorrhea after a few days, and  an HIV AgAb (4th generation) and syphilis blood tests in a a few weeks. Or have a conversation with your partner, either to confirm she has been tested negative recently -- or perhaps to be tested now. If negative, of course no risk and nothing to worry about.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

I think I know what you may say but I normally wouldn't be concerned by oral sex at all, as I have read your opinions and other experts opinions on this. 

It was just that i had felt a spot/ pimple on the top of my mouth that obviously fell off and then, after the oral sex with ejaculation, I could feel a little pain/ discomfort at the top of my mouth. My concern was that there was possibly an open cut or lesion and semen may have come into contact with it.

Kind regards and thank you greatly for your responses and help.

One risk calculation for oral sex, penis to mouth, is that there is one chance in 10,000 of infection for the oral partner if the penile partner has HIV. That's equivalent to giving BJs to infected partners once daily for 27 years before infection might be likely. If some sort of oral lesion doubles the risk, that's still only one chance in 5,000 or 13-14 years of daily BJs. (And most like double risk it too high anyway.)

Does that help?