Get him into the vet. How old is Vinny? He could have injured himself somehow (nerve or fracture), or calcium deficiency can cause paralysis too. He also could have had a stroke, and from what I am reading paralysis from strokes is temporary. Only a cavy knowledgeable vet can tell you what is going on.
Have some x-rays taken to make sure it is not an obvious injury and go from there.
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