I'm not seeing anything fundamentally wrong with the head other than I find it to be a tad fuzzy, but I'm not entirely sure the concept of a "watermark" is really sticking with you...
The shading around the very bottom of the nose looks abrupt, but other than that it's great. It looks like you toned down the shading around the hood though, any reason for that? Diggin' the new watermark by the way.
I realized that the yellow color wont work with any sets. SO i changed it to grey. This is the finished one. Can't be arsed fixing it anymore. Added some shadows to the cheeks and suff.