You know, I'm just going to play devils advocate here for a minute, so don't kill the messenger.
I don't think the OP is exaggerating at all when she says her mom yells at her at least twice a day.
13 year olds are at an age (this much I do know, I had to deal with it) where refraining from "yelling" at them twice a day would be a miracle.
i.e. this hair conditioner story. The OP doesn't say if in the end it was discovered it actually was in the bathroom. Was it there, and for the upteenth time a 13 year old is saying they can't find something when it's right there. That can be crazy making.
How do you know that she would have slapped you in the face if you hadn't gone to your room? From what I read, there haven't been anything physical since spankings when she was little.
She gets angry at you for the stupidest reasons? Maybe it's because you're doing stupid things and she's at the end of her tether.
Of course her face changes when she gets angry. Everyone's face does.
If you're scared and depressed, imagine how she must feel. You don't trust her? Maybe she doesn't trust you.
She raised you well up to this point. Could it be that you're at a stage where you're being scatterbrained, selfish and driving her nuts?
Just a thought.