I love it! As I was looking at the picture, I was thinking about all of Batman's well known battles in the books, games and cartoons and wondering how does he hide the scars from women when he's living life as Bruce Wayne. This took me to some good places in my imagination, and that's what we strive to do when we draw something and put our hearts into it. You did that very well. This picture says a lot....kinda tells it's own story. Great work.
the pose is great and the set up is really good. I haven't used Gauche too much myself yet I found if you used it a bit thicker then water color you got a good result. The only thing I think you are missing on this is the shading of the muscles on Bruce's back. The scares looks really good. It is at the upper part of the lower neck and traps that you miss the shading. Overall though, this is a very good piece of work. NICE JOB!