Where is your body? Unless you have a killer neck beard growing. In which case I apologize; it is amazing.

My joking aside-- it is cute, but it does look like you either have a neck beard, or you're in a sleeping bag and have an enormous head, or... or you're a baby in a cocoon blanket. I'll stop now. DD; I'm sorry.

Don't be afraid to draw a body! I think it would be much better with at least a neck and some shoulders.

Well, the lineart around the face is pretty bumpy, but I can understand. Lineart takes a while to grasp. So basically try and smooth it down. My technique, which you may or may not wish to adopt is (after you have finished the initial sketch) if you are using, say a 200px squared canvas, resise the image to 400px squared. (Be careful to pick image size, not canvas size.) You  used a 4-5px brush in this picture? Do out your lineart, if you what a thinner finish, I'd suggest using a 3-5px brush, if you want a thicker finish, select a 5-9px brush. Make sure that the lineart is smooth or else it will not have a good outcome when you resize it back to its original size. After you have generally smoothish lineart (Hey, practice makes perfect ;D) resize it back to its original size, 200px squared, and you should have some decent lineart to work from. Oh yes, if you didn't know already, px stands for pixel.

One more thing, on your self portrait, your eye seems to consist of pupil only. Try to steer away from this as this is generally an animal feature, if you look at a picture of a human you will see a large portion of the eye being white. As Grayvs said not to be afraid of drawing bodies I must say don't be afraid of drawing eye whites! c: