D.S.
Hi D.
My son was the same age exactly when he developed "night terrors". He would wake up screaming and asking for me but didn't recognize me when I tried to comfort him so of course it just made things worse. He's now 19 so it's been a while for me but I do recall that turning on the lights was the one thing recommended that helped the most. The only other thing you can do is keep them safe, push things out of their way and protect them. Once we turned the lights on he'd start to wake up and be fine. I can't remember how long this lasted but I don't think it was more than a year or so. Good luck!
D.