To bug face - to behave freakishly tweaked, usually as a direct result of being incredibly high. May also mean to get very pissed off.
Phrase has not been witnessed anywhere besides New Jersey.
Possibly related to the Jersey term "faced" which means being rediculously high to the almost max. Being high to the max would be "judged" or "slain", or something else to that effect.
I was buggin face bro!
Dude, I threw a snowball at him and he bugged face!