If the woman is married(and there is eidim and hasraah), the man gets killed. If she is single, he has to marry her and can never divorce her. If he is ashkenazi, he probably has to give her father 50 silver coins.
It could be he also get lashes for violating the “Lo tihie kedeisha,” though it may depend if thats what she was.
All this is in addition to kares, which he gets if she was a niddah.
If she was not a niddah, she was probably under age, which would be statuatory rape, and hell probably go to jail.
If she was not a niddah and not underage, she is probably about to get married, and her fiance will probably kill them both.