I don’t know if he came in me

Hi everyone. I’ve been on the pill for about 5 years now. I have a new significant other, and haven’t been sexually active in months. We have sex with no other form of protection except for birth control. Earlier today we had sex and he came on me, but I think maybe a little got inside me. I’m not used to letting someone cum inside me. I’ve only let someone do that twice and I didn’t get pregnant. But I’m worried for some reason.. my period is about 3 days away and I’m cramping and getting pimples. I also take my pills perfectly, never late and have never missed in the entire 5 years. I just need some reassurance.