This is a very good drawing. What I can see clearly is an understanding of the structure of the head, what lies underneath, so that you are able to do the difficult task of drawing it in this perspective and very convincingly too.
I'm going to guess that you used a photo,(I could be wrong), which I make no objection at all, I use photos as well. I'm saying this because I took a look at your page here on deviant art and read that you are mostly self taught and have not taken any classes. Working from a live model will enhance your already impressive ability. A lot of people will tell you what you already do is just fine as is, but if you seek to always improve than it can keep getting better and more meaningful to you.