Three weeks ago I picked up two prostitutes in Southeast Asia. I made out with one of them and they both went down on me (unprotected). After discovering that they were actually men, I ended the situation. I had picked them up right on the street for very little money, and they seemed very unconcerned with the risk of the entire situation. They didn't ask about my health, and they didn't seem to have condoms, or at least they didn't care about putting one on me before going down on me. At one point, when I was paying and leaving, one of them indicated that the other used drugs, I can only guess that these drugs involved needles. Anyway, I have noticed that for the past week or so, there is a painless sore in my mouth, behind my teeth but before my actual throat. It is the same color as the rest of my mouth, but is definitely a strange bump. Just below this sore, the skin in my throat seems to be more white than pink. I just touched it while looking into the mirror (and immediately washed my hands). I don't know what I was expecting, all that I learned is that touching it does not cause pain. My genitals appear to be normal and healthy, by the way. My questions are:
1. If this is syphilis, and I get a blood test tomorrow, will I definitely test positive after three weeks, since a sore is present?
2. If I did get syphilis from kissing the prostitute, that means that an open sore was present in his mouth. Does this pose a risk for being infected with HIV during this experience, if he has the virus?
3. If this person had HIV, could their saliva have traveled into my system through my urethra?
4. I have read that syphilis is very easy to catch. If it turns out that I have syphilis, should I notify virtually everyone that I have been around since this experience occurred?
Thank you so much in advance for your consideration in addressing my questions.