Regarding feeding/gutloading the crickets, superworms, locusts, roaches, etc you can use a wide assortment of greens and veggies such as dandelion greens, kale, endive, escarole, collards, carrots, squash, zucchini, sweet red pepper, sweet potato, etc and a bit of fruit such as melon, berries, pears, apples.Veiled chameleons will eat vegetation sometimes which is why imho it's important to use non toxic live plants in the cage. They can be offered all the greens, veggies and fruits I listed for the gutload too.
Regarding the mark on its side...it is a burn and silvadene or flamazine will help it. I would move the lights up off the top of the cage. When you do...put your hand on the under side of the screen under the lights...you should be able to keep it there...otherwise iits likely to burn your chameleon again. For a basking light you can use a regular white incandescent household light of a wattage that produces the right basking temperature.
Hope this helps!