I've used an infrared sauna, the type that is large and you sit in it. I felt it helped with my swelling and stiffness. I used it in conjuction with a few other therapies at the time. I considered buying one at one point, but I'm in a rental so it doesn't make sense. Not sure about the type of unit you're talking about? Those tent type ones may or may not help. If you are near a large city, you could maybe find a rental at a spa or tanning salon.

I actually bought an infrared heater that works well in winter to heat my limbs when they get cold.