Red heat lights are notorious for promoting health issues and accelerating pyramiding. You could look into some cheap LED cob spotlights and neutral white 5600k, they actually have quite significant UVB output as well.
You could also get yourself a zester like a really fine grater and grate some zucchini or cucumber maybe some greens till it is a fine mush. That would allow this little guy to forgo the trouble of biting but allow it to scoop food up on its own.
Just lube up the tube with small amount of mineral oil and let the torts reflexes guide it. I would contact the seller about a partial refund. If you see any yellow/green scabbing in the mouth then it pretty much confirmed. The sad part is, it hardly ever gets better but if you have the time and...
This sounds like complications or a tortoise herpes infection, the first place they manifest is in the mouth. A large percentage of the Florida sourced sulcata have one or more strains of tortoise herpes do to bad breeding and multi-species housing. What the dry skin is probably nutritional kale...