hey
Hmm, I think it looks far too purple, and still not enough contrast.
I also advise you todo some sketches, try draw yourself from many different perspectives as possible, and not just strait on. Get to know the volumes that make up your face, maybe you can also try paint with different lighting positions also. The more practise the better.
I also like the look of rim highlights when it comes to shading skin

, to see what I mean checkout the mention of it (page 10-12) in the slides from
Stylization With a Purpose: The Illustrative World of Team Fortress 2. Hmm, maybe this is a result of indirect lighting, or the way the light scatters on the skin, I'm not exactly sure.
edit: This is probably sliding away from what you should be focusing on, but I just wanted to mention them

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cyas