I had unprotected sex (mistake #1) with an older guy who I don't know at all (mistake #2), but he didn't have any sores on his penis, and we only had sex for like 25 seconds, if that. If he didn't ejaculate in me and didn't have any sores, could it still be likely that I get a STD from him? He said he doesn't have any STDs, but people lie, and I'm obviously nervous. If you have unprotected sex, how long should you wait to have a Pap smear done to get the correct results? Is four weeks long enough? Is one week too short?