How does the author use metaphor in the novel, The Thing About Jellyfish?

One example of metaphor can be found in the way that Suzy compares the knots and tangles she gets in her hair to the way her friendship with Franny got knotted up when they started middle school. While Suzy could cut out the knots she found in her hair, she didn’t know how to handle the knots she was beginning to encounter in her life.