I would say you can make the color shading and color transition smoothier. (unless it was intentional - both effects can do good when mastered).
I think you can use more contrast: the shapes are defined by the shades. I feel like you may not care for realism, but studying it is very important because you learn which parts of the body can be exagerated in each face and situation.

But on the other hand you know what you are doing with the light and how it will behave. And i give you credit for that because many people don't know this.

In the end i think you should spend a tiny bit of your time analizing faces (and which parts you can exagerate on them) as well as howto master 100% the technike of colouring you choose. Keep improving.

Look at those freaky cheeks. It's like Howie Mandel, Lex Luthor and the ventriloquist doll from Goosebumps had an illegitimate butt-child.

You said make you feel like shit.