It is hard to say for sure what's going on without being able to see it. Pictures will definitely be a big help for us to help you!

What kind of bedding are you using? How large is the cage that its in?

If it is only minor scale discoloration, it may just be that it's time to clean the cage, or the substrate you are using might be staining the scales. Can you provide us with a little more information?

-Jen