My Lower Lip And Jaw Quivers. When This Happened Previously

My lower lip and jaw quivers. When this happened previously my Dr lowered my thyroid medication as my levels were too high,which corrected the problem. When the symptoms returned I went back to have my blood work done and this time my thyroid levels were too low so he adjusted my medication to correct for this. Now my jaw quivers more than ever. Could this be caused by something else?