trixie has the same hair as fluttershy. It would appear that fluttershy uses conditioner and a flat iron on her hair to make it look fuller and give it a wavy look while trixie doesn't seem to use anything but probably combs it. You can literally tell that her hair is dry as shit and probably has a lot of dandruff. Trixie's hair also seems to be more straight than fluttershy's but that could be just because fluttershy takes care of her hair way more than trixie does and you can also see some breakage as well around her tail. I also put a depiction of trixie at the bottom if she used a as much makeup as Rarity does for comparison.