Sexy watercolor = initial thought.

Critique = the nose feels overall flat due to shading/line work.  It's not that it's paper flat, but it seems like more depth could be found there.  The shading on the lips doesn't seem to match the global shading.  Other than this, the facial proportions are nice and the coloring itself is nice.  The figure jumps to the center of attention, the background is detailed without detracting from the focal point.  The main point I'd say could be improved is just overall shading of the face.  But overall, it's a lovely piece with minor flaws that are likely to be unnoticed by many people at all.  

8/10 score in my arbitrary number system.