I think he scratched me...

Okay, so me and my boyfriend recently had sex and before that he was fingering me (roughly) but after we had sex I started bleeding really really bad and I looked in the mirror to check and make sure everything was okay and it looked like I had a scratch inside my vagina. This has never happened to me before so I don't know. I was thinking I popped my cherry but I don't see how that's possible if we've had sex over 15 times. Advice please.