Just some suggestions, but you could also try giving her face more definite lines and creases, maybe a scar? This might give her a more realistic 'rough' appearance, as the problem with the original plastic 3d face is not the smoothness of her skin, but more that she has no defining features and lines. For instance, around the mouth and eyes. Try and think about what her flesh would be like, how the light would catch it, that kind of thing. It never hurts to look at photos and paintings for reference.
More natural colours and tones will help too - the green you've chosen for the shadow isn't quite right. Try just using darker skin tones for starters. I often find a hint of purple can then deepen those shadows in a natural looking way, as normal daylight shadows are purpley-blue in hue, not green.
Her eyes could also do with some highlights/reflected light, as they look a little dead at the moment - even a small pinpoint of white on the pupil can make a huge difference in my experience.
All that said, I'm just starting out with learning to paint skin properly myself, so these are just some of the things I've noticed along the way. Others may have more experience and better tips.