Can you tell us what your basking temps are? and how are you taking them ? stick ons? infrared heat gun or a digital probe? And what UVB are you using brand and bulb please?
Karrie
Poor little gut, I agree it looks like vomit. What size insects is the baby eating and what are the temps in the tank ? Answering these Q's is super important to be sure it doesn't happen again. If insects are too large and/or temps. are not high enough in the basking area [ about 100-105 ] that can cause inability to digest the food. Hydrate him now by dripping water on his snout. He may not eat for a day or 2 but if he's healthy he should bounce back, just be 100% sure the insects are smaller than the space between his eyes.