Hmm this is a pretty kool head texture. As Gulo said, it looks cartoonish at the moment. If you aren't aiming for this category then I suggest you add a lot more detail, as it looks slightly empty right now. I really like the colours you have chosen, it seems to really suit it. I can't wait to see the final copy. There, I will give a long and criticising comment on it.
For what I see at the moment, I like it. So I would rate it 6/10 right now.