Yes...absolutely too high...you're to dehydrating his small body....and overheating him. It should be cooler at night. You don't need heat at night unless your room gets colder than 50F at that age.
Is the black light a UVB producing black light or just a black colored
Incandescent bulb? Either way, it shouldn't be used.
Is the UVB light a compact or long linear tube light?
Mealworms are not the best insect to use. Try, along with the crickets, silkworms, BSFL, roaches, small superworms, once in a while waxworms. Feed the crickets and roaches and superworms with greens such as dandelions, kale, collards, endive, and veggies such as squash, zucchini, carrots, sweet potatoes, sweet red pepper, etc.and Avery small amount of Apple, pear, berries, etc.
Tongue issue might be because he's losing nutrition or it could be from too much UVB and D3.