So, someone actually posted with a similar issue on these forums recently. Let me link you to that:
https://forums.larian.com/ubbthreads.php?ubb=showflat&Number=933894#Post933894They weren’t able to find a satisfactory resolution, so I think that bug… er, unfortunately… killed their honour mode run. It’s a pretty egregious bug. You should definitely report it.
Hopefully others can find chime in if they have solutions in mind. You could try browsing through Nexus Mods, the website, looking for anything that might help. I’m not super familiar with the mods available.
With other games (much simpler ones though… Stardew Valley), I’ve been able to go into the game files and delete a save and revert to a backup save. But I kind of doubt that would be available here.
You probably can’t Misty Step down there either? Worth a try. Or could you use Enhanced Leap to get back up to the portal where you entered the astral prism? Can’t remember whether it closes or not.
