How quickly after having oral sex with someone who has genital herpes would symptoms start?

Low risk; a few days: It is possible to catch oral herpes by performing oral sex on someone with genital herpes, but quite rare. The risk was higher if your partner had an actual outbreaks (genital sores etc) but extremely low if he or she didn't have symptoms at the time. If you were infected, you will probably have symptoms (oral sores, maybe severe sore throat) within 3-5 days, rarely up to 3 weeks.