SOS - advice needed ASAP

I need everyone’s thoughts. My boyfriend and I were having a bath and we ended up have sex which ended up in the bedroom. He also was slightly being more rough than usual. It was good and everything, however, at one point when it was rough, it slipped out but it was all in a random motion and then we saw a little bit of red on his penis and idk what happened but after that sex was a little painful but I kind of ignored it because I have that somethings which we think is related to endometriosis or something. After we finished we found brownish blood and that’s never happened before so I’m a bit confused. So I’m not sure if it’s the roughness or the pressure of the water or something else.

Anyone have any advice or think they know what it might be? (This is not our first time)

TW/TMI: BLOOD IMAGE BELOW