You can always schedule another appointment and try to talk to the doctor. Although they rarely change their mind, I have seen a few cases in which the doctor was persuaded to, at least, increase the disability rating based on the specific complaints of the injured worker. You may need a lawyer to help arranger for the appointment. Good luck.
I would strongly suggest that you consult with a licensed Texas Attorney for assistance with your claim. Generally speaking, insurance carriers will be in constant contact with all Authorized treating physicians regarding your care. Often, a Nurse Case Manager will be utilized to be present at your appointments and/or speak directly with the doctor following your appointment. The goal for the insurance carrier is to have treatment be completed as inexpensively and quickly as possible. Scheduling an appointment with the doctor to "change his mind" will likely have no result. Again, there may be legal options available for you that would be best pursued with the help of a lawyer.