Hi I have doubt about unprotected oral sex. Do unprotected oral sex 100% not able to transmit HIV even though there is ulcer in the mouth ? For a receiving oral sex from a HIV unknown sex worker. Assuming she is a HIV positive.
She would have to have a significant amount of bleeding in her mouth to infect you in that manner. Saliva does not transmit HIV. Saliva contains antibodies to HIV not HIV itself.
http://www.medhelp.org/posts/HIV-Prevention/Waiting-to-get-tested--HIV-exposure/show/1378611