The muzzle is lopsided. Then lines you drew to indicate the edge of the snout are being used as a hard edge on the rear side, rather than the contour that it really is, so it looks cut off and pulled forward. You also drew the lower jaw horizontal to the paper, not to the axis of the head, so it looks tucked in.

cge0361 his the points I was about to mention. To add to his reply, you should study noses and eyes, take note of how they are shaped and structured IRL, and then try to replicate that in a drawing. The final shape of the nose is a lot more complicated than a simple triangle, and they vary between species. The eyes are a lot more than just a window with flash shapes pasted onto its cavity, there are the eyelids, the eyelashes, and the folds of skin where the eyeball meets the occular orbits.

PDF Literature: http://acid.noobgrinder.com/Loomis/

Loomis' Figure Drawing for All It's Worth is the recommended starting point, I think.

Thanks, I'll look into it.