What treatment for hemifacial spasm that causes upper lip to twitch up and left eye to wink uncontrollably?

Age is 73. Damaged from upper Invisalign tray. Botox treatment around eye and one to left sideburn area caused face to droop objectionably. Acupuncture under left nostril gave temporary relief but reoccurred when retainer use continued. Desired use of upper retainer causes additional spasms. Could one botox injection just under left nostril reduce the spasm? (Doctor says it will cause face to droop.) Could a minimal Botox dose be tried directly under the nostril to see if spasms are reduced?