This is probably not the correct book (2014 so too recent, Cotton is the protagonist's distant cousin, only a side reference to red licorice), but for the sake of later querents The Boys of Blur.
Twelve-year-old Charlie Reynolds has no idea what to expect when he moves to Taper, Florida --- Taper’s beloved high school football coach, Coach Wiz, has died, and Charlie’s stepfather, Prester Mack, is going to replace him. Charlie can tell that there is something strange about this place, but can't quite put his finger on it until he meets Cotton, who tells him that this small town is filled with haunting tales about the sugar cane fields. Charlie begins to wonder if his encounter with an enigmatic man named Lio, the mysterious disappearance of Coach Wiz's body and the blood markings on the town church lend credence to the stories.
It ultimately turns out that there are zombies named "the Gren" in the swamps, governed by a swamp witch. Like I said, it's not a great match, but someone else looking for books set in swamps with characters named Cotton might be helped. :)