Did you set the makeup at all? I can't tell if it's the paint looking shiny, but if not then I say tone down the highlights or use something less shimmery. The shading looks really good though.
Personally I would make your lips a bit darker- troll lips are naturally black, though most cosplayers seem to leave them gray on the males for some reason. A dark grey would be a good compromise though, and make it look more natural then skintone-matching lips. Otherwise, it looks good!
As a non-makeup side note, it looks like you're wearing red contacts- karkat's eyes are dark grey/black in-canon, along with all the other trolls!