You could try applying something like Lanacane moisturizing anti-itch lotion.
It has benzocaine to quiet the itchy nerves.

I think it is worthwhile to figure out why you are having nightmares. When I had them, I was not breathing right or I had my head and neck in a bad position.

Thoughts you may have earlier in the day or as you are going to sleep can also set you up for nightmares. There is a lot online about reducing nightmares. Google 'preventing nightmares.'

You could try taking a supplement of 5-HTP an hour or two before bed. Maybe 50 to 100 mgs. Magnesium w calcium also helps sleep.

I used to sleep with chenille gloves. It helped my hands relax, especially when I had tingly hands due to carpal tunnel syndrome.