They look fine to me, the sharp highlight lines give a plastic vibe but I think that is intended for the barbie look, perhaps the outline could use the second darkest share instead of the darkest one, but this is it, I sincerely don't have much to add to the hairs, nice work. The reddish darkest skin color showing through the hair's alpha is clashing with the hair color, I would go for a more purplish desaturated shade with enough contrast with the dark hair. Also the jaw lines read a bit like banding, but think that is not the focus here.