I found this topic because this just happened to me last night.
I had nightmares all night last night, one of the most vivid being that i was on fire.
I woke up today and didnt notice anything until i was getting out of the shower, i had burns all over my back in multiple areas. Places i couldnt even reach. They were not there yesterday. I wore a shirt showing my shoulders and upper back yesterday and they were not there. And as for the 'friction' comment, bullshit. I slept on top of my covers and was naked when i was sleeping i always sleep naked.
I got scared and google searched to try and find some answers, this place is the best I got.
For now, im being prayed over and getting my room blessed and I'll let you knkw how it turns out.