In "Beyond the Wall," Daenerys faced one of her greatest losses yet. She'd flown up north to battle the White Walkers and wights that were swarming the tiny little rock Jon Snow and his men had been marooned on. But while dragons were usually Daenerys' ace in the hole when it came to getting things done, this time it wasn't so easy. Viserion was killed by an icy spear and later turned into a wight himself. But can Viserion be turned back to a regular dragon on Game of Thrones?
Characters have come back from seemingly impossible situations on this show before. Jon Snow rose from the dead. Daenerys stepped out of more than one blazing inferno. Jorah survived greyscale. The odds were stacked against all of them at one time or another, but they made it through to the other side of their ordeals with barely a scratch. Why couldn't Viserion do the same?
The trouble is that so much of the White Walkers' magic is a mystery. None of them have ever been shown to revert back to who they were before they became the icy undead. They weren't brought back to life in the same way characters like Jon or Beric Dondarrion were, where they appeared to be mostly the same people as they were before. The transformation into a Walker or wight changes someone entirely, and it seems irreversible.
That's in part because Jon and Beric are actually alive again; the wights are reanimated, but they're still dead. There are pros and cons of both methods of bringing someone back. The R'hllor way allows for life to be continued normally, just with some extra stab wounds and a new hairstyle. You can also come back as many times as your nearest Red priest or priestess allows. The White Walker technique results in diminished chatter, ongoing but slower decomposition, and a blue tinge to the skin. The biggest bonus is that Walkers are nearly indestructible, but once they're killed again, they're gone for good.
As of Season 7, Game of Thrones hasn't indicated that there's a way for a wight or Walker to be brought back to life like Jon or Beric. I wouldn't put it past a determined Dany to find a way to figure it out, but it seems unlikely that Viserion will return to normal in the future. Far more plausible (and more disappointing for the Mother of Dragons) is that Viserion will only face a second, more final death once battle ensues between the living and dead once and for all.
Unless he uses his brand new ice dragon skills to usher in a second ice age, of course. That would guarantee Viserion's survival, but it still wouldn't bring him back.