The nose and mouth are all wrong, but... Other than that?

It could be a perspective thing, but I feel the ear looks too pulled back from the face. It's also a little high.

The nose actually looks okay to me in terms of positioning. It might be because of personal taste, but I think showing a bit more of the face on his(?) right side might look better because right now, I'm getting the feeling that the face is sunk in more than it should be.

That's about it, I guess? xD

The mouth is actually fine. So you're good! The main throw-off is the nosebridge, which is shaded a bit too narrow and tall for the perspective you're going for. Also in accordance to perspective, the eye's elongated as if you can see the character's entire face, rather than the 3/4 view you want.
Hope you don't mind that I redlined your piece. If you would, use it as a guideline and apply your own style. :) happy drawing, mate