Wtf is going on???

This morning I was with my boyfriend and he was fingering me. After I had an orgasm he stopped and he had blood on his fingers. My period ended on September 13 so I’m extremely confused as to why this has been happening. I’m just so glad that he doesn’t mind it at all and continues reassuring me that it’s ok, but we’re both wondering why this is happening. He doesn’t have long nails either. Does anyone know why this is happening?