Hi- Iguanas HATE change. And I mean they really hate it. Some iguanas are better with change than others. Some worse.
My iguana who doesn't mind small changes, i.e. changing the branches around, new bowl, etc. Really hate a new cage. When we moved her to her new cage she layed on the cage floor for three days before even moving at all. Then it took her another few days to regain her appetite.
Just make sure your ig stays warm. I wouldn't doubt it if he started eating again within 2-4 more days...anywhere in there...its just up to the individual. Its really hard on them.
I think in your case forcing food on him or forcing water on him will do more stress. So just leave him be, offer food and water in bowls near him, and no holding or petting. He should perk back up in no time.