The game has turned dark and it will not let me change the gamma. What can I do? I'm on PS4.

huh. weird

it is

If you go to the game’s save data on your console, you can see up to 4 files. 1 of them is for the game settings, and the other 3 are the save files. Delete the settings file to fix the gamma issue. You’ll just need to reset any settings you previously set when you get back into the game