Responses

it is possible to cause your own injuries. I can explain it like... blushing. A response to stimuli where blood flow is increased to your cheeks, ears, nose, and neck. Even during sleep paralysis, it is possible (though rare) to be scared enough that your brain is wiggin' out and sends signals to your body to create a response to internal stimuli as opposed to an external force.
Oh my god that's exactly how I feel when I have sleep paralysis and it's fucking terrifying