if he needs to go to the vet right now, he needs to go to the vet right now, no matter his preferences. If you are worried about being bitten, you can use a towel to wrap him up or a pair of gloves. It will be stressful for him for sure, but if needs medical care then he needs it and doesn't get a choice.
However, if this is to prepare for a future hypothetical visit, then I would recommend: take your time. How old is he? If he is under 4-5 months old, leave him alone: young panthers do better without the stress. However, you could start handfeeding him all or most of his meals. Pairing your presence with his food is a good way to increase your value in his eyes. Right now, you should not be worried about him climbing on you so much as "not puffing up when I enter a room". Picking up his safe stick, or trying to otherwise force him onto your hand is not going to help, and may hurt what you are trying to so a great deal. Asking a chameleon who isn't comfortable with you just being in the room to climb on your hand is like asking someone who is nervous of the height of a ladder to jump out of an airplane! Building trust takes time and positive, relaxed interactions. Start offering him his first couple food items from your fingers or from a pair of forceps/tweezers. Hold one item out (preferably his favouite) and hold very very still for 2-3 minutes. It may help if you don't stare directly at him, and stand sideways so you aren't looming over him. If he doesn't take it, drop his meal in his dish and walk away. My roommate had to do this with my cham- he hated her so much that he hunted her with intent to bite. Now she can move him around the apartment no problem. We just started with her hand-feeding him twice a day, for several weeks, until he was eagerly coming up to the front of his cage to see her, expecting food.
