Hello and welcome. My name is ***** ***** I'm a biologist with a special interest in reptiles. I'm sorry to hear that Chester is having trouble shedding. You have taken a good first step by spraying him. Moisture does often help. Instead of spraying, I recommend a good soak. Prepare a shallow bath consisting of 1/2 Pedialyte (yes, the kind made for human infants) and 1/2 water. Soak Chester for at least 20 minutes. Be sure to supervise closely. You may have to hold him in the water if he doesn't want to stay there. Make sure he has surfaces, such as rocks, that he can rub against.
If the remaining skin doesn't come off after a couple of soaks, it would be best to see a reptile vet. Snakes normalyy do shed all of their skin at once. When they don't, it can indicate an underlying health problem, form an injury to an infection. If you end up needing a vet, this link has a directory of them:
If you have more questions, let me know in a REPLY. I hope that a soak or two will result in the skin coming off.
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