This is a medical malpractice case. Appellee, Domingo Perez ("Perez"), as next friend of Maria San Juana Morin ("Morin"), a non compos mentis, sued appellant, Edwin Owens, M.D. ("Dr. Owens"), and others after Morin, suffered a third-degree burn to her arm during or after out-patient eyelid surgery. A jury found that Dr. Owens, the anesthesiologist during the surgery, was thirty percent responsible for the negligence that caused the burn and found damages totaling $500,000. In four issues, Dr. Owens contends: (1) the evidence is legally and factually insufficient to show that he caused the burn; (2) the trial court abused its discretion in excluding the testimony of Margie Cornwell, M.D. ("Dr. Cornwell"); (3) the evidence is legally and factually insufficient to support the medical damages awarded by the jury; and (4) the trial court abused its discretion in appointing an ad litem to represent Morins interests and taxing ad litem fees against him. We reform the trial courts judgment and, as reformed, affirm.