How does the snake come to be in Jim's blanket? What does he do for the snakebite?

Huck tries to play a trick on Jim by leaving a curled up dead rattlesnake under Jim's blanket. But when Jim crawls into the bed he gets bitten in the ankle by the snake's mate. Jim takes the jug of Pap's whiskey and drinks himself into a drunken stupor to avoid feeling the pain of his swollen leg. It takes Jim four entire days to recover from the bite and Huck vows to never touch a snakeskin with his hands again.