How does the author use metaphor in the novel, Where the Dead Sit Talking?

The scars left on Sequoyah's face in the aftermath of what he says was an "accident" involving his mother and some hot grease are outward representations of his inner pain - specifically, the pain caused by the sense of abandonment, disappointment, and suffering that he has experienced throughout his life with his alcoholic mother. They are also both a literal trigger of, and metaphorical representation of, the inner suffering he has experienced as a result of the rejection and bullying he has faced throughout his childhood and youth.