Did I damage my frame by removing a sticker?
The shine is likely the residue from the sticker adhesive. I would apply some rubbing alcohol on a soft cloth and see if it comes off. As you haven't damaged the actual finish, it will be fine. I had a similar finish on a Diamondback Response. After its' first wash I waxed it. I thought I had ruined the matte finish. When the wax wore off the original finish returned.