Rhea

Since she is eating and burrowing I would work on the humidity first. The version that comes to me instead of to a thread has swollen or closed eyes, which in box turtles often traces to infection or a vitamin A problem, bubbles or discharge at the nose, noisy breathing, a soft or oddly growing shell, or floating lopsided.

Flaky discoloured skin alongside constant soaking is worth a look too. Mites and skin irritation push them into the water as well.

The two I would actually want to see. A respiratory infection gapes with bubbles or mucus at the nose or mouth, clicking or crackling, visible effort in the breathing, and a lizard that has gone quiet and off food. In a desert species it usually traces back to being too cold, too humid or badly ventilated.

Mouth rot is the other: redness, swelling, cheesy looking material inside, bleeding gums, and holding the mouth part open because it hurts rather than because it is hot. Neither of those is a lizard who shuts up and walks off to cool down.