Dear doctor, I had bad experience 3 weeks ago. One
Hello and welcome to ask a doctor service. I have reviewed your query and here is my advice.
Oral sex does carry risk of transmission of Hsv( Herpes simplex virus), Hpv(human papilloma virus), HIV. With HIV the risk is negligible if there was no ejaculation even though precum can be infectious. Moreover, saliva is not conducive for survival of the HIV. Still, I would suggest you to screen for HIV, HSV after 4 weeks from exposure.
Hope I have answered your query. Let me know if you need any more assistance
This could have been a new infection with Herpes simplex virus i.e labial Herpes/ Cold sore or it could be a Canker sore. Anyways I suggest you get screening tests for all STDs like HIV, HSV, VDRL at 4 weeks.
Let me know if you need any more assistance