It seems like you've relied on a lot of guesswork, especially regarding the facial anatomy. Some things that seem off to me...
The distance between the nostrils and the eyes seems really long.
The distance between the upper lip and the nose seems really short.
The 'smile wrinkle' (forgot the anatomical name) shouldn't end in the middle of the nostril flare...it should blend above it. Also, the mouth shouldn't actually connect to it.
The eyes seem a bit far apart.
The ears are gigantic and really inaccurate.
The non-human elements of the face, the bumps and ridges, seem really artificial. I think this is because they are uniformly sized and don't blend into the form, but rather seem stuck on.
The ripples read more like cloth.
I think you'd really be doing yourself a favor by utilizing reference.
I hope this helps, and look forward to seeing your progress.
Will design for food, provided that we all agree that money is edible.