Blinking procedure doesn't work

Hi! I'm trying to make a procedure that makes the player blink every twenty seconds and then after half a second open the eyes. However, this procedure just gives me a flashing screen that hurts to watch. How would I fix this?

Image: https://imgur.com/a/bk5PchR

Also I'm using a generator that is too old for the wait [] ticks on server-side do block