The Worlds We Leave Behind by A.F. Harrold
Hex doesn't know why he does the things he does-why he sometimes stands up in class to look out the window or ask an unrelated question or do a little dance. He also doesn't know why he threw the rock that day in the woods. He didn't mean for the girl to fall and break her arm. But he's blamed anyway.
Enraged at how unfair life is, Hex runs into the woods and finds himself in a strange clearing-a clearing that can't possibly exist-where a strange old woman offers him a deal: she'll rid the world of those who wronged him. All he has to do is accept and they'll be forgotten, forever. But what Hex doesn't know is that someone else has been offered the same deal.
When Hex's best friend Tommo wakes up the next day, something feels wrong. Half-whispered memories tug at his brain, making him think that something-or someone-is missing from his life. Can Tommo put the world back the way it was? Or can he find a way to make a new world that could be better for them all?
This unforgettable story, complete with lush black-and-white illustrations throughout, explores how we can find the strength to face down monsters: in the darkness, in our friends, and in our selves.-Goodreads