I have a 6 year old who woke up swollen on the side of her cheeks she has a rotten tooth do i wait for the swelling to go down b4 taking her to dentis?

Not likely: Since the swelling is likely caused by the tissues reaction to the rotten tooth, I would not expect it to resolve until the tooth is removed. At least call the dentists office & see what they would suggest you do to prepare for a visit.

Don't wait: She has a virulent infection that is spreading throughout her facial tissues. It will only get worse, not better. She must see a Dentist immediately before she winds up first in the ER, then in the Dentist's office. Please call for help now.