Looks to me like you dove into the detail before you got your basic form down.
Several things look off to me. The neck is too long ( the body is probably too far down ). The fingers on the hand are too long. The lower lip on the mask doesn't look right. The side of his head looks like its a bit too long, and the ear looks to far back. Something weird going on with his jaw. Looks like his forehead is too short, the eyes look to be about 2/3 to the top, should be about 1/2 way to the top.
I think it's a good concept, but if you want it to look right you'll have to rework a lot of stuff.