When you use abrasives or acids on tempered glass, it can sometimes (contrary to normal glass) develop a fog or haze. Is there a way to remove this?
Regrettably, tempered glass is very sensitive to any scratch or abrasion. The surface is under great stress, and a scratch can quickly propagate, causing the entire piece of glass to shatter into numerous little cubes.
There are some suggestions for polishing the glass, but realize that the glass is already compromised and might shatter during polishing.
If you cannot replace the glass, a temporary way to make it look better would be to cover the scratches with clear plastic spray. Unless you can find a product with the same index of refraction as the glass, though, it will not hide the abrasion completely.