If you have had your handyman work on your shower valve, chances are he had to enlarge the working space somewhat. In the process, the area can get damaged. This is the area right behind the shower handles and if you have tile walls, these can chip or crack. At that point you will be faced with either replacing the damaged tiles, or you may be able to cover them up. A decorative cover, which is also known as a beauty bar, can cover up this area. It basically functions as a large escutcheon plate. You can buy them in whatever finish your handles are in so that they match.
To install it, you will need to remove the handles. The cover will have the holes drilled into it and you can simply push the cover over the stems sticking out of the wall. You can apply some caulking on the back to hold it in place until you get everything situated. On older faucets, you can remove the decorative stem covers, install the beauty bar, reinstall the stem covers and finally reinstall the handles. When everything is back in place, run a bead of caulking around the perimeter of the beauty bar to keep the water out.