You didn't use the word "convulses" before, and that makes it sound more like some kind of a seizure than a persistent genetic wobble, (like spiders). I agree with anwhit, it might not be a bad idea to visit a vet, (preferably a certified exotic vet familiar with reptilian physiology). Of course, if the snake is eating and showing no other signs of disease you might just leave well enough alone and see what happens. If it were an exotic and expensive morph it might be well worth the vet visit, but if it's just a normal pet-quality snake you have to weigh the benefits against the expense. If the snake is eating it is likely not suffering, it might be unpleasant to watch but if it has a normal appetite it is probably ok.
S