Hey balls01,
I noticed you were having a little trouble with her lip amongst other things.
I've whipped up an edit to display how the lip may look:

Far from complete, just a rough edit to show how you may handle some things better. Looking back at it now, I'd probably add a little more shadow to the right side of her nose to show how slender it is, for instance.
When creating the lips, I added a ton of colors, that are likely unnecessary, sorry about that.
There are quite some many other things I've touched up upon too.
Such as the shape of her face / jawline. It is much more petite in the reference as compared to the roundness you have now. If you look closely, the side of her face goes down to her chin in a sharp angle.
I fixed her eyes and nose slightly to be a little more emphasized / correct.
Her facial features.. The current facial features you have aren't aligned properly (IE. The highlight on her chin for instance, is too 'horizontal', and instead should be parallel to her face.) I added some more facial features and brought them out more, as well as editing current parts to be more correct with the reference. You had some shadow/highlight spots that just didn't comply at all, and I do wonder why you put them in the places you did.
I would do a little more, because I've grown to really like doing edits, but it IS your piece, and not mine. You are the one that must learn from it.
Also, what I think TrevoriuS was talking about, was that you should define the muscle under the indent ('cut') a bit more, highlight it. And bring the cut all the way to the side of her arm.
Overall, though, I'm impressed with how far you've come since October (which is when you became active), and such little time.