Celluloid & Acrylic are notoriously difficult to glue. Seriously I would leave it until it falls off then you can use Epoxy or Selleys make a "Plastics Glue" they claim glues "ALL" plastics including polyethelene & polypropylene. It also works for metal to plastic. The trouble is, it needs a primer applied to the plastic surface first so it is only good for complete transfer not a touch up as you are contemplating.. I have used it successfully on a recent Filarmonica logo transfer. Much better than CA. If you choose to use CA make sure its a low bloom CA or it will haze... & look like crap