I would like to start off by saying, well done! This picture has got a fair amount of attention that it does deserve.
Now to some of the critique.
The horn is in a odd shape. The issue is with the spirals you have created on it. They seem to go flat on the right side of the horn then curve around at the end of the left. Make sure to keep the curve going or you end up making it look like a rounded cheese wedge.
The hair is interesting but it has almost become noodly. At one point along the left side of the image the hair goes a different direction than the bulk of the strokes. It is just ~5 lines but still a little off putting.
I think you could improve it all together by removing the bulk of the black lines and relying on your shading/highlighting to give shape to the hair.
The smoke coming out the eyes is really nice. The issue is with the left eye smoke. If you were to use a high opacity bush and add a opacity gradient to the smoke it would give it less of a HERE I AM look. The right side gets away because its darker.
The background is a really nice touch.