Not too shabby...
Eyes are far to large (Unless you were going for something like that?), the light source wasn't really planned out too well (The nose suggests the light is coming from our left, while the eyes make it seem like it's from the right and the overall face structure shows that it's from up top). Also, the dithering makes this piece far too noisy and it's definitely not necessary in this piece. Lastly, the banding on the eye lids is a real eye soar.
Don't get me wrong though, it's quite good and it's a definite improvement over some of your other pieces.
Keep it up. :)
Boa vsb!!