Upon further inspection (and looking at the pictures you so kindly showed me), I think part of what's bugging me about her lips is the line down the center - why is there a gold line along the center of her lips?

The cartoony effect is much stronger in the first image, without the detailed shading, so I think the issue is more about depth of shading than anything else.

I wish I could sit next to you and watch, for entirely selfish reasons; I want to get better.

Stasia