I've kept mine in a closed chamber since it was a baby and maintained 80%+ humidity and mine is a bit bumpy as well. I had uvb lighting in the enclosure for the first 2 years and wonder if it plays a part or possibly genetics or both.Of the three Burmese Stars that I raised up from hatchlings at the same time the smallest one always was a bit bumpier. I think some are just predisposed to it. But, it is possible something else plays a part that I am just not aware of.