Hi. Your guy definitely needs a vet to tend to the tail. I’d guess part of it is dead and aside from possible amputation, he’ll need some antibiotics to prevent infection. If you need help finding a vet, just ask and
@elizaann2 will give you her list.
Although you haven’t asked for husbandry advice, I do have to offer some. Sorry, but I tend to be a mother hen.

The enclosure you have him in, while it’s cute, is much too small for an adult male. The minimum standard is at least a 2x2x4’ or equivalent. Veileds like to nibble at their plants and don’t really understand artificial ones can’t be nibbled. Because of this, he needs to have all safe live plants. It only takes one nibble of a fake leaf to cause a serious bowel obstruction. For the same reason, mossy branches are discouraged to use too. You can use real branches that you can gather outside. Just avoid branches from trees that have sap or odor, like pine, eucalyptus, etc. Oak and birch are great and commonly found everywhere. Just clean in some soapy water and rinse well and they are ready to use. For plants, the easiest and most versatile is pothos. I like to put a large center plant like a schefflera or dracaena and then surround it with pothos, nerve plant, tradescantia and other common plants. You want to provide not just nice clean leaves to drink off of, but to hide under, take shade and nibble on.
https://chameleonacademy.com/plants/ I use my fake plants on the outside of my enclosures to give my chameleons more privacy from me.
Rather than go thru everything, let me direct you to
https://www.neptunethechameleon.com/ She has a video for just about everything and always is adding more. She also has partnered with Pangea in putting together a
real chameleon kit that is useful and the price can’t be beat.
https://www.pangeareptile.com/colle...sca_ref=2120335.Dn9y03RxpN&sca_source=website
If you need any help, advice or have questions, we’re all here. Do keep us updated about your big guy’s tail and what the vet says/does.