What does "lint" means here?
"Your high is wearing off, leaving a box of lint where your head should be. "
This sentensse is from a novel called Out of Body, describing a depressed guy is watching everything happends from the perspective of a outsider or a soul out of his body. The context is this "you" is getting high after doing drug.
What does "a box of lint" really means here,and what's that to do with the head?