77 is too low for a hot spot. how are you regulating your UTH and bulbs? you should also be checking the actual bottom of the tank's temperature and not on top of the substrate.
are these ambient temps? ambient should never drop below 75 anywhere in the tank.
not using hides is a definite sign of stress. "a hiding ball is a happy ball." with the temps you've provided it seems like she's not warm enough. try to get your hotspot to stay consistently between 88-90° and ambient well above 75°, closer to 80°.
those are called urates and are essentially urine. make sure to check and spot clean daily.![]()