My butt itches after I go to the bathroom, and at 2am, when I'm sleeping. Sometimes it wakes me up.?

THe most. Common cause of anal itching especially if it wakes you from your sleep is caffeine followed by excess perspiration. Do not use witch hazel! Cut out all caffeine and use corn starch powder on your bottom when getting dressed and whenever you feel dampness or itching in that area. Avoid petroleum based creams of any kind.
Nocturnal rectal itc. See your doctor for an exam and also check for pinworms. The worms crawl out of the rectum during middle of the night and cause irritation. There are many other possibilities so get checked up soon.