Number 1 thing, if you can afford it and if one is in your area (some areas have no herp vets), is call and make an appointment with a herp vet.
Secondly, buy some Betadine from walmart and mix it with a tub of water until it turns a light tea color. Then soak her for 10-15 minutes. (Btw before you add betadine, put the snake in the plain water because they like to take a drink when they're first introduced. After a few minutes, add the Betadine) After the soak, put some Neosporin (with no painkiller) along the entire length of scale rot. Repeat until you see the vet.
If you cannot afford a vet or one is not in your area, follow these steps listed above. If it keeps getting worse...
Good Luck!
-Andrew