Must have been some big d*ck

Ariana Grande

She wears a wig for the show so she doesn't have to keep dyeing it. She did dye it back to brown a while ago, but she hasn't dyed it since.

a lot of people were saying her hair was falling out because she's anorexic but I have no idea if that's true.

She's not anorexic. It's because she dyed her hair so much and it's not falling out that much, just enough to look terrible at times.