The part I bolded is key. Distraction can truly take one's mind off pain, and with a mild pain such as having needles inserted, the distraction may be enough for your pet to not even notice the pain caused by the needles.
If you are aware of the Lamaze method of childbirth, the principle is the same. The pain of childbirth is severe, but concentrating on the breathing patterns helps to focus the mind on something other than the pain, making the pain more tolerable.
A giant lizard, however, is not a pet and cannot be distracted in the same way. All I can think of is that the poor animal is being subjected to a lot of stress and pain for no real medical benefit whatsoever. That is cruel.
Had I believed that the treatments caused him pain I would not have kept bringing him back. I was there, and skeptical in the beginning. So, I observed closely. As long as he didn’t see anything, he was completely unaware. The sensation had to be minuscule.
If you need to believe that it’s painful because you oppose acupuncture, I’m certainly not going to change your mind. But, I know what I saw, he was not in any discomfort whatsoever and the treatments did benefit him as far as mobility and pain.