Some people cut their own skin. They take a sharp knife or a razor blade and make an incision. It causes pain and some scarring. Often they keep on doing it; they grow to depend on it as a release. As Kettlewell describes it, cutting yourself helps to narrow one's focus to one thing: the cut. All your other worries fade away for a while.
Of course, there's a downside to cutting yourself. Pain and scars are part of it, but really they don't seem to bother Kettelwell. More troublesome is that cutting yourself doesn't make your other problems go away. Indeed, it can add to your problems. You either successfully keep your cutting a secret, and so become more isolated from other people, or you get found out, and have to answer lots of questions.
Kettlewell spends a surprising amount of time describing her life when she was twelve and the few years following. She links her cutting with the start of her awareness of her body as a young girl. Once she started cutting, she continued for another twenty years. She was an A-student in junior high and high school, and she was neither extremely popular, nor an outcast. She had quite a few boyfriends. Once she got to college, she had many boyfriends, none of whom lasted. After college she settled down, got a job, and got married. But she hated her job and her marriage crumbled. It was only after several attempts at psychotherapy and eventually taking an antidepressant that she no longer felt the need to cut herself.
Self-mutilation is often associated with borderline personality disorder. Kettlewell never tells us if she was given a diagnosis, but she does tell of many traits associated with BPD. She was anorexic as a teenager. She was promiscuous in college. Most importantly, she feels a terrible sense of having no center to herself. She is very preoccupied in asking whether cutting means she is crazy, or whether she is just cutting to appear crazy. She doesn't seem to know why she cuts herself, and she doesn't know why she does anything. She has very little idea of who she is: all she is familiar with is how she appears to others.
Skin Game is a short easy read. There are a few passages where she graphically describes cutting herself, and squeamish readers may find those difficult to endure. But for the most part, her story bounces along at a fast pace; Kettlewell is an accomplished writer, sticking mostly to her story, with occasional more general reflections on the meaning of anorexia, middle school, cutting, and other central themes. She doesn't blame anyone for her condition; and she mainly gives the drug Paxil credit for helping her. If you are a cutter, you might find it helpful as a story of hope or it might be comforting to find someone else who describes the turmoil that leads to cutting. If you are not a cutter, Kettlewell's memoir might help you a little in understanding such apparently incomprehensible behavior.