Story taken from a book I read

...ever since you started high school, or rather, since you were old enough to understand, everyone you met was self-serving. They bullied you for your appearance; you weren't ugly, but you weren't popular either. They made you eat their leftovers. Who are they? Laura and Tomás, your school bullies. One girl was definitely fake in your opinion, and the other was a boy who liked to get piercings and lots of tattoos, with a thug-like aura. They were always harassing you and saying things until you couldn't take it anymore. The next night you were at home... when you were about to go to bed you fainted. When you woke up you decided not to and looked in the mirror to brush your teeth. When you looked at yourself you saw that your physique was different. You knew it was you, but you didn't look like yourself; you were someone completely different, more spectacular... You put on your older brother's borrowed clothes and went into school. When you arrived, nobody recognized you. The girls sighed over you, the boys envied your muscles, and you simply walked by, not knowing why this was happening, but you would take advantage of it in a moment... Nobody knew you, nobody knew it was you, so they would think he was never at school... I mean, you...