There a couple things you can try first, but more than likely you will have to take the snake to the vet for antibiotics. Try lowering the humidity in the cage and slightly raising the temperature. Be sure to have a full water dish in the cage though.
Take your snake to a vet who has experience with reptiles. Your python needs to have a culture taken to decide which antibiotics would be best to cure the infection. In the meantime it could be helpful to elevate the temperature in the cage slightly.
I would increase the warm side of the enclosure to 95 degrees. I would make sure the humidity is correct. I would take the snake to the vet for antibiotics.
