Hello and no, this is not a risk for HIV. Hand jobs do not transmit the virus and her spitting on your hand, her hand your penis or herself or whatever, spit in general will not transmit the virus. Air and saliva inactivate the virus. The only ways adults get HIV is from unprotected vaginal or anal sex or sharing IV drugs. No, you do not need Prep and in fact, don't even need to test as you had no risk.