kinda worried

this is dumb and there’s no exact answer but i’m a little worried and could use some reassurance.... last night my boyfriend came on the outside of my vagina, like basically he was just rubbing my clit and vulva with his dick, never went inside, and i told him to move to my stomach when he was close just in case bc there was no condom and im really REALLY not trying to get pregnant. i guess he got a little lost in the moment and ended up finishing where i told him not to (he was really sorry, it was cute😅). im like 99% sure he never went inside and i know there’s probably a super slim chance if any at all. im just extra extra careful and extra extra worried (i havent had sex with him yet because im waiting to get into the health department for some BC). sooo this is a super stupid question im sure but realistically what are the chances of pregnancy for something like this (i have no way of knowing if any of it went ~in~ or not, but obviously if it did it wasn’t very much). i just got off my period if it makes a difference