[Help] Metal polishing on front of phone

Hi, I recently got a large amount of relatively deep scratches on the front metal bezel on my HTC One M9. I (stupidly) tried 320 grit sandpaper to try and clean the scratches, but that left it looking like this http://m.imgur.com/tDAwOY6

Still, better than it was before. What could I do to give the front a more polished look? If I apply water/liquid to the area which I've scratched, it looks almost normal.

EDIT: The metal has developed a dark spot...might have gone too far http://m.imgur.com/Hb0EHoQ . Is it ruined now? Can't seem to get rid of it

EDIT 2: Well looks like I hit the bottom. http://m.imgur.com/CJnRCm0 not a bad look to start from I guess http://m.imgur.com/cyZJDjI