Stretching the jaw muscles isn't going to help nor hinder your recovery from mucositis. Here's an excerpt my therapist gave me
[quote]You may experience some discomfort when you begin your therapy, especially if you have had pain and prolonged immobility. Initially you should be gentle and only stretch to your personal comfort level, with time and patience you will increase your opening and decrease the pain you are having, by gently increasing your spam. Should you experience a different type of pain then normal or increased pain you should always call you doctor just to make sure all is well[/quote].
IMO, you should start now
Charm