I have done three different types of mirror repair depending on what the customer wanted the finished mirror to look like. 1. You can gild the bad spot on the back of the mirror with silver foil like any other gilding. This will make the mirror look much better but won't totally hide the damage or repair. 2. If the frame is deep enough you can cut a new mirror the same size and shape as the old mirror and mount it behind the old one, this will make it look better but the damage will still show. 3. You can strip and re-silver the old mirror, every thing you need is available through Kwick Kleen on line. This will make the mirror look like brand new but will hurt the antique value of your piece.
