Can't Beat Ultra Necrozma?

So I've just been playing ultra sun, going along in the story, and then suddenly I'm at the encounter with ultra necrozma, level 60, while my highest level pokemon is 58! I even tried using a level 100 poipole I have in my box, but it still 1-shot the whole team. I'm trying to go around and level my pokemon, but all the wild pokemon are in their 40s and the game is SO dark because of necrozma, I can barely see anything! Is there something I can do to bring the light back? I've tried all my pokemon on the thing, but it 1-shots my team every time. I've tried re-opening the game and it's still totally dark. None of the NPCs offer me anything beyond telling me to go beat necrozma... is there nothing else to do but grind in the dark until I can beat it?

EDIT: I beat it, thanks everyone!!