Hi kwt,

It would be wise to have a dental xray of the teeth on both sides of the missing tooth to evaluate the health of those teeth and the bone. The pressure from the elastics could have inflamed and possibly injured the periodontal ligaments and caused irreversible damage to the pulp of both teeth. The fact that they are loose can also indicate that some bone loss may have occurred.

The pain in the chin could be referred pain from inflammation and/or infection. It would be best to see your dentist asap for the xray and evaluation.

Hopefully it is just trauma related and the teeth are still healthy!