Holding Up the Universe by Jennifer Niven
Libby Strout lost her mother unexpectedly when she was ten years old. She ate her grief away, becoming morbidly obese and a social media spectacle. Jack Masselin is a popular guy, with lots of cool friends, but he’s working hard to hide a secret: he can’t recognize any of them from day to day as the result of a neurological condition that causes facial blindness. Jack and Libby’s worlds intersect after a bullying incident, and their resulting relationship ultimately enriches both their lives in surprising and wonderful ways.