I have to concur, this needs more shading; the colours you've used are so very pale that I could barely even tell that there was anything in the image, other than the two brows, at first. I like your choice of perspective, and I look forward to seeing where you go with this piece, from here.

I'm returning after an extended absence myself, and ironically enough, I've started out with something similar, with similar problems. But if my piece is too pale (which I firmly believe it is), this one is practically invisible. One easy way to change that might be to change the background colour, so that your pale choice of skin tone is against a dark/black background.

One other C&C -- the proportions of the face are good, from what I can see of it, but the shading on the nose makes it look just a little askew, based on a line from the tip of the chin to half-way between the brows. You may want to remember that the straight line of shadow (down the shadow side of the nose) is broken at the end by a small curve, where the tip of the nose flares out.

Good luck with this! :)