I will be using the Lexus touchup paint pen. How long after applying the touchup should I wait to polish and wax?

 

Depends on the wax. If your wax has cleaners in it, I'd wait at least 4 days just to be safe. When I did my car, I waited 48 hours, but that's with using pure wax with no cleaners.

Same goes for polish since it's essentially a cleaner.

It never hurts to leave the paint on a bit longer, just so you know it's cured already.