What is the importance of DEET in the novel, The Thing About Luck?

DEET is the name of a strong insect repellent. Summer makes sure she wears it all the time in order to protect herself from mosquitoes and the malaria she fears that they carry. Late in the narrative (Section 4), and in a moment of stress, she forgets to put it on. Her reaction when she realizes what she’s done (or in this case hasn’t done) is a defining moment in her process of coming of age - specifically, facing down her fears.