Please comment!

tell me this isn't done because it's awful right now
kind of looks like copypasta because of the white pixels near the solid black lines
it's pretty awful for a finished head (no back), but as a sketch it's OK

I wouldn't take Brains10's "advice" too seriously, I actually really like this head, it's nice simple and looks good. And commenting on the whole "not finished" thing, not all heads have to be fancy and look like it's been worked millions of hours on to be a good head. I really like simple heads, and especially sketchy looking ones as well, so I really like this head. Also on the back, if you plan on adding more, I would suggest adding some facial structure lines like you did in the front, just to have some consistency.

Brains10 is kinda right about the white pixels being covered by the black lines. And it's not proportional, like the ear is higher than the eyes and the other eye as too near to the nose.
But if you're going with simple head texture just like what Galard said... then it's ok, Except for the proportion thing.