I was told by my vet to up the humidity as well as the heat. This will help the mucous from solidifying. He also told me to bring it in the bathroom when you are having a shower. You can hang it upside down and gently massage downwards toward the head to release the mucous, as snakes do not have a diaphram to cough it up. You will definitely need to get it to the vet for antibiotics as that is the only treatment. Please do so as soon as possible as the severity of it can change quickly.