I know that oral sex is not a high risk activity. But, would canker sore in my mouth raise the risk because it's a type of open sore? For further information, the sore was small and seemed yellow without bleeding. it was located inside of my lower lip. I licked the semen right after my partner ejaculated so it was exposed to the air for seconds. I dont know if the virus (If he was positive) died due to that exposure to the environment.