gauche lips

What grabs my attention is the contrast you have in this piece... I mean the shadows are nice and dark enough and the highlights really bring out the 3D in the elements of the lower mouth. Even if there's high contrast, the colors all have a subtle gradient to it so it's not flat looking at all. Amazing job!

Few pointers; The frontal view (in the middle) has a very... artificial look to it. Like the nose has way too much sharp edges on the bridge it looks like an unfinished statue. The shading on the right side of the lip is off to the point the lip seems to be lopsided and wanting to move on it's own if you get what I'm saying (it's kinda confusing for me too <img src="e.deviantart.net/emoticons/a/a…" width="19" height="19" alt="" title="Sweating a little..." />). Also try drawing a center line on it, and try drawing horizontal lines to check symmetry. I know human faces aren't symmetrical at all but the basic balance of the drawing should at least have similar weight I think... and the direction of the nose, lip and chin seems to be going all in a different direction. Also the left nostril seems too shallow and doesn't look like there's a hole.

The profile view face is almost perfect though the highlights and shading loses some impact on this one. The nostril seems off? Too big? But the organic curve that leads to the hole looks like it's cut out with a sharp blade. Remember there's a round curve on the rim of the nostril.

I can't really say anything on the 3/4 view facing our left because it looks perfect. The shading, the geometry and the realistic skin feel is amazing. Maybe the left, darker area could use more darker areas around the lips and the lower jaw to prevent looking too flat but in general LOVE it.

The almost profile on the right is close to perfect but it definitely needs more darker shadows. The corner of the lip seems like a big circle and looks like a make up some clown would put on. The reflective light on the upper lip seems a bit strong too.