What Causes Vaginal Bleeding Post Unsuccessful Intercourse?

Hi doctor....yesterday I got close with my bf. We tried to have sex but I couldn t..he then rubbed my vagina with his penis.. A little blood was on his penis ...i thought hymen broke but he said it is not that..jst the skin got ruptured..the bleeding was very little...i cleaned it but back at home in washroom there was again blood. I am scared...i don t know what to do...should I be worried or it will be fine by itself