The Boy Who Lost His Face by Louis Sachar

In a 1989 suburban town, a boy named David tries to get in the cool group by helping his friend Scott, and two troublemakers named Roger and Randy (the former being the leader) carry out a prank. Their target was an elderly woman who was called a witch by all the kids in the neighborhood. When they attacked her and stole her cane David flips her off to try to impress Roger. But when they were leaving the old lady's house, she cried out to David "Your Doppelgänger will regurgitate on your soul!" The following days David finds himself experiencing strange happenings that lead him to believe that he is cursed. After being rejected by Roger and his gang, David finds himself becoming a loser. He breaks his parent's window, he walks into class with his zipper unzipped, he falls off his chair in class, and his only friends are fellow outcasts Larry and Maureen "Mo". His actions lead Rogers gang to target him and his friends, calling them "The Three Stooges". He becomes friendly with a cute girl named Tori Williams, but his pants fall down when he gets the courage to ask her for her phone number. Finally, his little brother, after being ridiculed by Roger's younger brother, loses all respect for David.

Eventually, David begs the elderly woman to remove the curse, but she asks for her cane to be returned first. As it turns out, Tori does not turn on him for his moment of humiliation, and tries to pretend that she had her eyes closed in thought to prevent David from becoming uncomfortable around her. David finally decides to fight for his dignity, and, with his friends and little brother by his side, he goes to face Roger's gang and get the cane back, not suspecting that many things, including the curse, are not as they seem.