Hit in the Chin, sore jaw, and face. go seek a doctor?

my friend got hit in the chin with a vase, the other day at pretty close range, and his jaws real sore when he moves it around, and up near the ear on the opposite side hurts, and theres swelling. When should i make him go seek a doctor? He says its fine, would hurt more if it was broken, just wait for the swelling to go down...