Dawn, what you are trying to do with the heat and exercises is to gain flexibility and strength in the jaw muscles. They are like any other muscles in the body that become sore and tight.

Now if your pain is shooting type pain then that would be best treated initially with cold towels until your pain becomes more of a soreness rather than a sharp pain. A shooting type pain would indicate potential muscle spasm which is exacerbated by heat. But after it calms down with cold packs (usually 24-48 hours) you can then start the heat/exercise program. Use your judgment

A way to really provide excellent therapy to a muscle group is to use heat for 7-8 minutes then cold for 7-8 minutes and then heat. This REALLY creates blood flow and stimulates healing.

Best Wishes!