Screaming in sleep

[clzj]

My 13 month old has started screaming hysterical in his sleep at the same time each night. He sleeps fine during his naps and after this.

I wondered if anyone else had any experience of this and why it might be happening?

Does he actually wake up? How long does the scream last for?
MY DD had a period of time where she would let out a bit of a cry but still be asleep and would settle back down. I usually just shushed her a bit and laid my hand close to her so she’d know I was there.
Have no idea what it was though. Could it be teething pain?