Actually H does use acid free paper to wrap scarves. All of their scarf boxes have acid free tissue paper.So sorry your scarf has become discoloured, and hoping it can be fixed.
In addition to mold, you might consider acid damage from the tissue paper and cardboard box in which the scarf is stored. I doubt H uses acid-free papers to wrap its products. In either case, the box will have to go, and you'll have to rethink your storage options.
Good luck!