what are you using for UVB? if it is in one of those domes, the first thing you're going to want to do is replace it with a long straight tube and fixture. and is that dial the only thermometer you have? you'll want 2 probe thermometers. they are the most accurate. that dial is only giving you ambient temps. the uvb and heat are the absolute most critical for their health and the place to start with any troubleshooting. once that is on par, if issues are still happening, it is easier to figure out what else could be going on.
here's a link for the thermometers.
Zoo Med Reptile Terrarium Digital Thermometer | reptile Humidity & Temperature Control | PetSmart
the link i have for the light says they are sold out. but
@KarrieRee should be around here and she'll have links for other sources. she's the one you're going to want to work with on the lighting/temps. she's the best!