What main changes does Paul Fisher go through?

Paul Fisher goes through a variety of changes. He is a dynamic character who grows and develops throughout the book.

At the beginning of Tangerine, Paul was  a weak pushover who allows his brother to mercilessly bully him. He had low self-esteem due to Erik’s relentless taunting. However, at the end of Tangerine, he became an empowered and decisive young man with the power to  stand up for himself and his friends. These changes were primarily motivated by his move to Tangerine Middle School and his growing understanding of Erik's cruelty. 

 First of all, Paul's family moved to Tangerine from Houston. This major change should have allowed  Paul to begin anew, but his hopes for a self-reinvention were dashed by his parents’ focus on Erik’s burgeoning superstardom on the football team. It was a negative change, given that Tangerine held new dangers (muck fires and sink holes) and the same old problems as Houston; for example, Erik quickly got up to his old tricks and found new lackeys to torment Paul. Consequently, the first major change to positively impact Paul was his move to Tangerine Middle School, where he was able to make new friends, experience success on the soccer team, and gain the necessary confidence to confront Erik.

When Paul saw  Erik’s lackey, Arthur Bauer, demean his new Tangerine friends and fatally injure Luis Cruz, Paul underwent  a change of heart. He found himself no longer able to stomach Erik’s cruelty, and he joined his friends by attacking Erik and the football team at an awards ceremony. He also regained his memory of how he lost his sight back in Houston (Erik and one of his friends spray-painted his eyes.) Consequently, Paul gained both knowledge and power.