I tried drawing perspective lines over the face, though I had a bit of trouble with the box. One thing I notice you're doing is that it seems like you're interpreting contour lines as a perspective point, and not 'seeing through' the form to where the other points are (e.g. occluded nostril, occluded lip). I'm interested in seeing the other answers about where the box is.

I think you could put the vanishing points a little farther apart. I see the head as tilted away from us a bit, so I'd draw the horizon line at an angle accordingly. Here is what I'm seeing...

Hey Toto, It's great that you are thinking about perspective with your drawing. The thing is that the face is so small, that the features are very subtle in perspective. The vanishing point is so far away that its not really noticed. Instead, it's better to just make sure your features are lined up and parallel to each other. I hope this quick little drawing will help :)