Hello.
Sorry, but I am pretty skeptical about taking it to the vet just because of a 'bad mood'. Myself, I'd want some evidence of a physical problem, before I'd put my lizard through that kind of a scare. Think about how the lizard sees it; restrained and put in a carrier, vibrating, noisy car, strange brightly lit room with a strange large human poking and prodding and shining bright lights in its eyes. Think of the sharp smells and the barking of the dogs. And of his body temp. dropping to room temps, which means its helpless to defend itself. Also, of course, being held and restrained from struggling.
It's no big deal to US, as we know no harm will come to it, but how do you tell the animal that?
The baby that hisses and whips doesn't hate its owner, its just untrusting. And it feels alive and perky enough to defend itself. Be gentle with it, and give it time. Not just a month, expect longer. How long would it take to befriend a wild squirrel or bird? A while. Well, this is a wild animal too. It needs you to be patient.
If you are afraid of getting bitten while cage cleaning, etc. try holding a rubbermaid lid as a shield in front of the baby, then do whatever you want with the other hand. It should just whip the lid, then realize that was pointless, and just stand there.
If it runs around the edge to see what you're doing, you got a smart one! hahaha, JK.
D.