Should I get Plan B?

I am probably overreacting but I want to ask to be safe. There was no intercourse involved with my boyfriend, we only made out and gave each other oral. He came and cleaned up. He didn't pee or anything. Then we started again, gave him a head and I saw precum. After a while he started just rubbing his dick on my pussy (I remember it just rubbing my clit and the lips). I'm just scared some of his precum had sperm in it and stayed around my hole for hours and "came in" my vagina? I know it sounds so impossible because sperms don't live for a long time.

(I didn't let him put his dick inside me because he didn't have condoms.)