Help diagnose my T!!

[KHolyoak]

Hey Guys,
I’m a T newb and I tried to find the species category for my GBB(Chromatopelma) and I couldn’t find it. I turn to you all her for some help though. My T has a weird dry skin on her abdomen. It’s been there for a few months and after her not eating last night( she was almost scared of the cricket, I took the cricket out after she didn’t eat it) I figured she is pre-molt. Pic provided, it’s bottom left of her abdomen.
One user suggested this is dandruff?
Any help is greatly appreciated.
Again sorry for posting this in the wrong species category.