your mom is doing that hysterically over-dramatic, pointless thing that people do when they realize they no longer have control of a situation and they’re scared shitless.
but this is a brave new world! one in which you are responsible for your own actions and really, very few of your decisions reflect on her parenting skills now. this should be a liberating time for her.
so here’s what i think you should do: be the mature one. be the one who’s not hysterical. don’t be surly either.
don’t wear a fucking wig for christ’s sake and don’t hide in your room.
remind her that the holidays are about spending time with family and loved ones, not judging people based on their appearance, and that you’re more than just a lip piercing or a haircut (both of which are impermanent, by the way); you’re the same person she held close and rocked to sleep nineteen years ago.
thank her for raising you to have the confidence to express yourself in safe, fun ways. and then continue on with your holiday vacation as if this case were closed, because it is.
basically just show her that she’s behaving like the most petty, superficial twat on the planet, but without actually saying anything similar to that.
don’t call your mom a twat.