The judgement of whether or not glass can be fixed is if it can be felt under your fingernail, it usually can't be polished out without special tools and polishing media.
I bought one of those cesium oxide glass polishing kits from CR lawrence, (automotive glazing supplier), a while back and tried to polish out a little scratch I put in a windshield .It had Cesium Oxide powder and a hard felt wheel that you put in a drill. I think Eastwood might have something like it also.
I was there for hours and got nowhere.
A lapidary supply,(rock and gem polishing supply), or a marble /granite fabricator might be able to set you up with some diamond dust or something similar and a suggestion of what kind of grinding wheel or lapping plate to use to polish your glass with. Maybe a small piece of lapped granite would do. That's what I'd try.
Flow coat it with clearcoat. ?? maybe?
Buy new glass?
I know little about polishing glass but I ran into this on a Mustang windshield I bought at a swap meet, for 10 bucks I thought I would give it a try since it was only a small spot. I used one of those glass polishing kits, I forget the brand name, and I polished forever on that darn thing with no luck. Sometime later while having a windshield replaced on another project I mentioned this to a guy at the glass shop (they also do glass "polishing") and he told me it depends a lot on what it was blasted with because usually sand cuts way to deep to polish out. He said that even if you could cut it deep enough it would probably cause distortion and could even cause tempered glass to break.
My truck windshield has some deep scratches in it. I post pics on another forum last year and asked about polishing it out. A gentleman who worked in a glass shop for years, said that even the machines they had would not do it.
If you can feel it with your fingernail...its not fixable.
I would imagine that sandblasting goes as deep or deeper than my scratches.
He was correct. And even if it was polished until it "disappeared", the polished area would be distorted - it would act like a lens. Also, it would take hours upon hours to do, and at shop rates these days the labor could easily cost more than new glass.