[Image: http://i.imgur.com/0OAw8.jpg]
You need to make the chin smaller, or not exactly position it with the guide-line. It's too wide.
Is it a chibi, or..?
I'm no professional, but I'll try and help--
[Image: http://i39.tinypic.com/6o35zl.png]
Excuse the size difference in the green heads + any repeating of sh*t. I rushed the explanation.