lefty,
it is entirely possible for the joint to heal itself (not really, but often the dog can manage just fine with the damaged joint). some of it depends on the dog, some depends on treatment/therapy and a lot just depends on the exact nature of the injury. regardless, the pain part of the immediate injury will quickly fade away.
i'd recommend spending some time googling around.
btw, turmeric and fish oil has almost completely alleviated (for now) my dog's arthritis symptoms.