Keeping rice paper spring rolls moist
In its recipe for Spring Rolls, What's Cooking America indicates:


  Spring rolls can be made a day ahead. Cover them with a damp paper
  towel, then wrap well in plastic wrap, and refrigerate. Refrigerating
  firms and toughens the wrappers and noodles [inside the roll, in this recipe] slightly (if they are a
  little dry, wipe them gently with a damp cloth).


In the future, consider that you might not want to make the rolls until you are ready to eat them.  Your filling ingredients will probably hold quite well on their own, and hydrating the wrappers to make the rolls is very fast and easy.