I performed oral sex and received as well from a guy, he didnt ejaculate in my mouth, should i start pep since its hasnt been 72hrs,im scared hiv?

Neglible risk: There is a negligible risk of HIV transmission with oral sex, so there would be no indication for PEP. Syphilis and gonorrhea and less commonly Chlamydia could potentially be transmitted with oral sex. I would advise that you get a urine, oral and possibly rectal (if prior) check for GC/Chlamydia and a blood test for HIV, syphilis (treponemal antibody), hepatitis b and c.