I'm new in the plummie world, but I will try to answer this. Lack of watering during winter time doesn't normally kill a plumeria. Check if the bottom part of the stem is still hard, if it is, this should perk back right away in Spring when you start the regular watering/feeding schedule. Check the tips, I read somewhere, that a shiny tip is a healthy tip. Spider mites caused damaged to the leaves of my Dwarf Pink Singapore plants I kept indoors but now that our weather is warmer and I brought these plants outside, they are looking healthy again, with no signs of spider mites. The leaves where the spider mites feasted look pale/washed out green though but other leaves are healthy green.
