well she certainly has a wicked wicked corkscrew going on.
Couple of questions....do you have any boas or has it been around any boas in the last 3 months?
Do you have 2 of the same hides one on the cool side and one on the warm side?
What are your temps and how are you controlling your heating device.
A couple things come to mind...first of all IBD from being exposed to a Boa. Or this could be a heat issue and the temp spiked and caused this. As far as her being to skinny...I don't think she is at all. Typically they will get a pyramid shape and you will see a pronounced backbone when they are too skinny.