Per instructions we brought our pottet plumeria inside for the winter and put it in a dark room where the temp usually stays around 65 degrees, but somehow the door to the room got closed and the temp has fallen to who knows what. The plant is about 5 ft tall w/ three spikes about 6" long. Two of the branches are getting soft as is the main trunk about 1/4 of the way down. One branch is still hard and looks good. I assume the plant got too cold. Di I cut it back now to good hard material? How do I save it? thank you.