My three year old jumped off of the top bunk last night onto another bed and hit his knee on the bed fram. This morning he couldnt walk on it, but was not swollen or swore to the touch. I gave him ibprophen and iced it, he is walking now but cant run and cant walk upstairs or straighten it out. He isnt in any pain though. What might be the problem and should I just watch him for a few days and make sure he rests the knee.