I'm a uni student just had a casual sex on 28 August with a guy with unknown hiv status (seems somehow sexually active) in China. I lied on him, did frontage with my penis over his pubic zone (I intentionally tried to avoid having direct contact with our glanses and I did check on his penis with hand occasionally to make sure that we're not touching, he wasn't obviously wet as I was, but I still can't be absolutely sure if he had precum and if it went on my penis/foreskin/glans), and we did mutual masturbation. We're both uncircumcised, both of us ejaculated, on his abdomen/chest. We didn't have any kinds of anal penetration nor oral sex, though I did suck his nipples. I washed my penis/glans with bath briefly and rinsed my mouth with water. I'm still very concerned about:
1) Is there a chance that I may get hiv or any other kinds of std from him if he's infected?
2) Is there a possibility that HIV may be transmitted by having his precum touched/rubbed on my inner foreskin under this circumstance? I've been testing routinely for hiv and it's constantly negative.
3) I'm planning on doing a STI check up next week (3wks after this encounter, I've never had anal sex before, the last encounter before this one was in January, did oral and mutual masturbation), would the results be accurate or I'd be better to wait for a while?
Sorry if I'm being paranoid and thank you very much!