I am currently working with a snake that has the same problem and my way of helping it is making it better.

Dilute some betadine to a tea color. In a seperate container, mix 50% water and 50% peroxide mixture.
Use a Q-tip with the betadine mixture on it and brush the gums, then use a different q-tip with the peroxide mixture and brush it on the gums, then go back over with the betadine mixture again(different Q-tip to be safe)

Do that once daily for 2-3 weeks, then every other day until it is healed. If it gets worse then take the snake to a well experienced vet.