Description from Open Library:

Chase's memory just went out the window. Chase doesn't remember falling off the roof. He doesn't remember hitting his head. He doesn't, in fact, remember anything. He wakes up in a hospital room and suddenly has to learn his whole life all over again . . . starting with his own name.

Description from Google Books:

When Chase returns to middle school after falling off the roof and losing his memory, he learns that the person he was before the amnesia is not someone he likes.