Casey has access to plenty of makeup. With the sunshine laws in Florida, a list of everything the woman buys with her prison account money is available to the public. Makeup and junk food are her main purchases. It may have been Greta that revealed what what on the list.
But she’s not wearing any makeup in court. Also, I think the lawyers can provide her with makeup and clothes. On channel HDL (I think that’s it), they have a court photo of her wearing a nice suit and looking professional. It looks so much better than the ill-fitting blouses she’s wearing every day. I’m only saying this from the Defense’s point of view; why have her look slovenly?