So getting right to the point, I am a 24 year old male that lives in Massachusetts and have been heterosexual my entire life.  Recently, I used a gay hookup sight as I was curious if I would enjoy being with a guy as I have never tried and always wondered.  I ended up meeting up with someone considerably older than me (50) around 10:00am wednesday morning and giving him oral sex for about a minute before I stopped cause I realised that was not my cup of tea.  Later that night around 7:00 I noticed that I had a small ulcer/cut looking thing next to my second moler on the inside of the roof of my mouth and now im petrified I got HIV vause there was some skin missing.  I decided not to get PEP as i saw many say that its not warranted for oral exposures but im terrified.  Some backround info:

-No full ejaculation occured (maybe precum?)

-Individual SAID they were negative and had a test in May.

-This was my first and only ecounter.

I guess my questions are:

1. Should I be worried? Could I have HIV?

2.  Should I have gone on PEP or do you agree with my (slightly) educated decision

3. If i want to get a test when and how would i go about that and do you think its necessary?  

Thank you so much Dr. Hook/Dr.  Handsfield!

This event was exceedingly low risk for HIV -- zero risk for all practical purposes. Your brief statement is correct, i.e. PEP usually "not warranted for oral exposures" and I would not recommend it.

Oral sex in general is very low risk. Only a very few cases have ever been proved to result penis to mouth (and none at all in the other direction, i.e. mouth to penis). For your situation, based on how HIV infected persons believe they were infected (which often is wrong), CDC has calculated an approximate risk of one in 10,000, and that's only if the penile partner is known to have HIV and not be on treatment for it. It also assumes ejaculation in the mouth.  To put that in context, it's equivalent to giving BJs to infected males, with ejaculation, once daily for 27 years before transmission of the virus might be likely. And not only did your partner not ejaculate, probably is isn't infected:  people rarely lie about HIV status when asked directly. So I would put your actual risk at something like one in a million, tops.

I don't see the sore in your mouth making any difference. If you think about it, oral sores of various kinds -- also bleeding gums -- are extremely common, so millions if not billions of exposures must have occurred in their presence, and still HIV transmission risk remains near zero. Neither I nor Dr. Hook have ever treated or even heard of an HIV infected person whose only possible exposure was oral sex. And in response to your follow-up comment, it isn't blood per se that can raise HIV risk, but its source and amount. Whether or not your oral sore was bleeding doesn't alter the risk calculation.

Those comments pretty well address your questions, but to be explicit:

1. You should not be worried; there is no realistic chance you were infected.

2. I definitely agree:  no PEP.

3. Testing for HIV is not required in this situation, at least nor from a medical or risk perspective. But of course it's optional: the reassurance value of a negative test result often is greater than professional opinion, no matter how expert. (We don't take it personally!) If you find yourself worrying despite understanding the risk issues, have an AgAb blood test (i.e. 4th generation) in a few weeks. It would be nearly conclusive (98-99%) at 4 weeks and 100% by six weeks.

The only other consideration, of course, is other STDs. That risk is higher than HIV, but still low. Syphilis could be an issue since it's epidemic in men who have sex with men -- although still low risk assuming no obvious open sores on his penis. Herpes in theory, but extremely rare. Oral gonorrhea -- but unlikely if he didn't have visibly abnormal discharge. But if you like, you could have a throat swab test for gonorrhea.

I hope this is helpful. Let me know if anything isn't clear.

HHH, MD

2. Saliva indeed kills HIV and it's generally assumed that's part of the reason oral sex (or exposure to oral fluids) is pretty much risk free. But stress on "assumed"; nobody knows with certainty. There's no point in doing research on zero risk events, right? Whether oxygen per se does so I really don't know. My understanding is that air exposure is important because HIV dies rapidly as the fluids it is in dry out. 

3. Ohio person's comments make sense, but here too I think he was making logical assumptions without data.

People can say whatever they want about this forum, Reddit, or other sites. I'll just say you're wise to look for data and opinions only on professionally run or moderated websites, like this one -- and be very careful about those by and for people at risk, with a particular health problem, or worried about it -- like Reddit. You're really been into the weeds on this. I suggest it's time to end any and all online research, telephone advice, and anything else. It isn't worth it.