Been happening to me past couple nights where the paralysis starts at my hands (as usual), then my right thumb will start to feel hard and try to bend backwards.. followed by a couple fingers on the other one.. they bend to the point where my brain reads it as painful.. I can feel my astral body moving within my physical at this point which is bizarre too... just not sleepy enough to get to the vibrational state.    

All kind of sensations can be experienced during the mind awake/body asleep stage. Just enjoy them and experience all the variations. Nothing can harm you. It's all in your mind.