In the novel That Was Then, This Is Now, how does Bryon "get even" with himself?

In Chapter 11, Bryon is laying down reading a book when his mother says to him,

"Bryon, you got even with Mark for Cathy, then you got even with Cathy for Mark. When are you going to stop getting even with yourself?" (Hinton 156).

The traumatic events that Bryon has witnessed and life-altering decisions he has made have left him emotionless and callous. Bryon is no longer the same person he was after he sees M&M experiencing a bad acid trip. Byron is also haunted by the memory of Mike Chambers and stricken with guilt over the death of Charlie. When he discovers that Mark has been selling pills, he calls the authorities because he is sick of seeing innocent people hurt by others. Bryon feels guilty and confused about telling on Mark and gets even with himself by breaking up with Cathy. Bryon neglects the girl he loves and begins to live in a "shell." He becomes reclusive and does not care about having fun or interacting with others. Bryon essentially feels like he's ruined every relationship he's cherished and feels extremely depressed. His introvert personality and melancholy mood are also ways in which he attempts to get even with himself.