There are several kinds of figurative language in chapter thirteen of Love Medicine by Louise Erdrich, and the most obvious example in this chapter is metaphor.
One of the pervasive metaphors in this chapter is a smokescreen. This is the metaphor for the things both Grandpa Nector Kashpaw and Lipsha Morrissey use to hide behind when they need or want time and space to think. Nector sings songs out loud in the middle of mass and tells the same stories repeatedly, among other things, which make people believe he has gone crazy. These are part of the smokescreen he has put up between himself and the world, giving himself time to think. Lipsha says he understands because he puts up his own smokescreens, at times.
A related metaphor is "second childhood," which is another excuse for Nector's foolish behavior. It seems to be connected to his diabetes, but calling it his second childhood makes it a metaphor.
He would stand in the woods and cry at the top of his shirt. It scared me, you scared everyone.... Grandpa has done things that just distract people to the point they want to throw him in the cookie jar where they keep the mentally insane.
A second major metaphor in the chapter is Lipsha's "gift." That is a metaphor for the special inherited ability he has to understand and heal people. He touches people and "they feel much better." A related metaphor is the term for which this book and this title are named is "love medicine." Love medicine is using power-containing objects, tokens, or talismen to induce love in people. It is not real, as evidenced, by the events which happen in this chapter; however, the thought of it seems to have a positive effect, as it does on Grandma Kashpaw.
The entire book is quite poetic and contains many other forms of figurative language, as well.