Help! I think I'm pregnant

My boyfriend needed some help getting into the mood last night, so I kindly started to help him out so we could get the condom on and get the show on the road. Well, while I was doing that, some pre ejaculation fell out and near my lady parts. I don't think anything fell where it didn't belong, but he quickly went and grabbed a towel and only wiped off the side of my delicate parts where he thought he saw something fall. My question is, if he didn't get it all, is there some way he could've rubbed it into my vagina? Is that a thing that happens? Should I be concerned? Please help!