Berc:
The hair should be strands. Look how the hair falls over the left side of the face.
The eye brighter, and a more defined shape of the light around it.
The face is great. But I don't like the top lip.
The mutated side should be darker, and the chin should be slightly illuminated around it.

Follow the reference more closely and it should turn out great.

knightz:
Are you using gimp? Instead of posting a spinning globe, create a spinning globe, but save it as a png. Removing layers so it turns, and then save it again. So you can post the head from different angles while stationary.