Unless your friend is a trained vet, I wouldn't let her swab or put tweezers in the snakes mouth. Nature has a way with dealing with these things, I'm a believer that something like that, it's best to let the snake do it's thing. That may be wrong, but fighting a snake to get into its mouth like that may end up doing more harm than good vs just letting him be for a while.

You should take him to a vet and explain all of this. You should probably wait at least a week before feeding again to let him heal from this ordeal. Then give him something smaller, as mentioned above. Best of luck to you though.