Apparently, there is no reason NOT to try physical therapy, regardless of how long it has been.
Last spring I was experiencing popping of the jaw. It was unpleasant and painful. I scheduled an appointment with oral/facial surgeon, but couldn't get in for some months. Shortly after getting scheduled, I injured an ankle badly and spent three months on heavy anti-inflammatories and the popping went away. I kept the appointment though.
The surgeon confirmed what I had known - the left cheek (the affected side) muscles were very thick, and also very stiff. This was pulling my jaw out of alignment. My jaw was also generally stiff. So after talking through possibilities and options, we decided on anti-inflammatory that is gentler on the stomach then the diclofenac I had been taking for my ankle and physical therapy. He had one in mind that was local and good with facial issues.
She was wonderful.
Not only did she tackle the jaw alignment and range of motion, she worked with me on trying to reactivate the dormant facial muscles and synkenesis.
It worked. Surprisingly enough, in less than eight weeks I had noticeable improvement in function and symmetry. The spasms are reduced and I can do things with my face I couldn't do before. It also seems that is continuing to improve, albeit slowly.
The thing is, I had given up long ago, accepting my asymmetry, synkenesis, and a left eye that blinked if smiled, chewed, or did just about anything. I was alive, my voice was back (and it also continues to improve), and life was good. I even did a blog post (https://randomdatablog.wordpress.com/2017/02/19/seven-years-of-asymmetry/
) about the asymmetry and my acceptance of it.
The exercises are hard and frustrating. Trying to move just one or two muscles I find incredibly difficult. Doing so and trying to open my wider (or just keep it open) is harder still. It's worth the effort though...I can see the difference, even if no one else notices it.