Front tooth knocked out and put back in, it's very loose. went to the dentist today and they said to go back in three weeks as it's too sore to x-ray.

See Endodontist: Tooth should be splinted for two weeks and taken completely out of contact with opposing teeth. X-ray should be taken to create a base-line. you should be on soft high/protein diet, nothing too hot or too cold. Do not bite into anything with that tooth. See a room canal specialist, and Endodontist, immediately to splint, x-ray, and evaluate the viability of the tooth's nerve.