Sheeesh. Brat is right. I probably would have shot back a "and what happened to your manners, did they get lost on the way to school today?" or just given him the look and said "Excuse me?" in that tone of voice. I do the "excuse me" bit with my own kid when she says something rude or otherwise uses bad manners with me.
Kids nowadays don't have a clue as to proper behavior, as it's not being modeled at home for them. That's one of my personal pet peeves.
I'm sure your hair looked fine. Kids are just so.....you know what I mean.