restoring drawing history

Hey so I drew this picture here, without the sporadic eraser marks everywhere. I, very briefly, tapped around with the highlighted tool on the left, trying to figure out what it was, then suddenly my picture looked like this. Despite the fact that I was working on it for over an hour, my file history shows that the picture wasn't saved, conveniently, until after whatever happened here. Is there any possible way for me to get back my drawing?
