Oh sorry! Must be someone with a similar name
I don't know if there is anything you can do to stop the swelling, except possibly rest. I would take him to the vets tomorrow. Which cage is it? I can't imagine a bed with a lid
If it's a house near the top of the cage then it might be an idea to take levels out and just have a house at floor level with his food and water nearby for now - so he can't climb or be too active and make it worse. So it kind of makes it into a hospital cage. Keep his nest though. If you've got something like a cardboard tissue box or shoe box you can cut the base out of and cut a hole as a door, that would do well on top of the substrate and pop his nest inside it.
Is he still using his wheel?