Sex and the morning after.

The situation: Character A got massively drunk and when one of his friends, Character B, tried to return him to his hotel room to sleep it off, they ended up in bed together. Character A wakes up the next morning, half-naked and in bed with one of his best friends. He can't remember anything from the night before, past approximately his third or fourth drink. He definitely doesn't remember consenting to sex. There is physical evidence of their activities though, so he can't really mistake the situation. Character B was also drunk, but not as far gone as Character A. Both characters are male, and there was plenty of preparation and lubrication.

My questions are these:

1) How much discomfort would A be in if he hasn't been on the bottom for several months? How long would it take for him to be capable of walking properly, so that he can face his other friends without worrying about them working out what happened?

2) What legal issues would there be about his inability to remember giving consent? One of his other friends is a major stickler for the rules, and may choose to do something about it if he finds out that A can't remember what really happened. Would the police charge B with rape, even if A is relieved that it was his friend and not some random stranger from the bar?