I had a guy who similarly trashed a knife of mine many years ago. It sat in a drawer for a long time til I decided to do something about it. I sharpened it up well (reprofiled the edge) and then started working on the scratches.
I've got a dremmel tool and used one of the polishing tips w/ some polish rouge. I started w/ the higher grit and moved down to finer. I used a slower speed. It removed the scratches pretty well.
If you're going to keep it as a user, give it a try, you might be surprised at what you can do.