One simple remedy, which many people will vouch for, is application of ice. When you have a painful or a swollen jaw, then cold compress in form of an ice pack can work wonders for you. This is in fact one of the standard home remedies for swollen jaw. When there is infection and inflammation, blood rushes to this site, which in turn leads to swelling and jaw pain when opening the mouth. Applying ice pack tends to reduces this flow of blood, and helps the swelling to recede and alleviate the pain.