Had mine done years ago now, my main piece of advice is afterwards, even though you don't feel like eating, eat.
The GA can give you a really bad stomach if you don't eat, after i'd been throwing up for a while i rang the hosp up and they advised eating anything i could bear, bread soaked in milk, sucked. yuck but worked.
otherwise, nothing else really happened, small bruises on/under the jaw, that's it.
Good luck