injury will be healed daily, so if you have 10 days injury it will be gone in 10 days. I never put my fighters to rest when they still have 80% or more energy after a fight.
I don't think it's applied on QFC. if your gym have sauna he will automatically go there. http://www.mmatycoon.info/index.php?title=Gyms. if your fighter signs with an organization, buy a weight loss supplement.