I haven't heard of this machine but we have a Tens which didn't alleviate facial pain at all! It probably depends what sort of pain. I would stick to the pain killers especially if you can get free prescriptions.
There is a practice called 'Touch for Health' which is very successfull for muscle pains and many other ailments, even colds and carpel tunnel syndrome which I had from wringing out endless nappies.You could google that to find a practioner in your area.
Pain is awful and I wish you well.
T