Can you give us some background, some context? What is this? What's the desired end-result? It's just kinda random and weird right now.
She's got a dead zombie green face, yet has typical brown hair and is smiling. Random and weird I said . . . why do I think that? Why have I not been compelled to comment before now? I think it's because, like my comment about the strange skin color, implying undead or zombie or something, and the normal girl hair causes a confusing contrast that fights against really giving me any sort of pure impression or understanding of your work so far. So it confuses me, causing interest in it to escape me, even though I want to like it, I can't.
Now with the blue face taking shape, it's starting to turn into something. Still don't know what.
But do you understand what I mean? When you survey something, and you don't really get any sort of discernible vibe or emotion from it, you're not engaged by it. It holds no power. Here, I'm far from captivated. It's almost annoying to look at, because I can't reckon what it really is. It's conflicted in and of itself.
Hah, what ridiculous postbarf, but I hope you at least partially understand my POV now, since I expect others share it.
One thing I wish you would do is stop finely processing just pieces of this before you have the whole thing sketched out.
Don't you plan on drawing both figures' entire bodies? - your OP says it's part of a larger peice. By all means you should at this point already have rough lines establishing the basic shapes of everything. It's foolish to blindly micromanage just one little bit at a time. Give yourself an overview of this piece, in context, as you create it. Doing that guards against backtracking - as you make progress you may get to a point where you suddenly realize you need to make a compositional change but it's too late for that, since doing so would mean having to re-work some areas you've preemptively refined too much. And that's painful! Especially when you could've easily avoided it had you just planned things better, with a complete rough draft done first, etc.