Botox Injections for Patients With Persistent Facial Pain

Inclusion Criteria: * Persistent Idiopathic Facial Pain fulfilling diagnostic criteria as classified in The International Classification of Headache Disorders, 3rd edition (ICHD-3 beta version) as modified by the authors of this trial. See below. * Unsatisfactory effect of available treatment methods as evaluated by a neurologist, ENT specialist or maxillofacial surgeon. The patient should have failed treatment with both anticonvulsant as carbamazepine (Tegretol, Carbatrol) and antidepressant as tricyclic antidepressants * Average Pain intensity ≥4 (0-10) in Numeric Pain Rating Scale (NRS) on the affected side during the 4-week baseline period * Written informed consent from the patient Modified diagnostic criteria for PIFP according to The International Classification of Headache Disorders, 3rd edition (ICHD-3 beta version): A. Facial and/or oral pain fulfilling criteria B and C. B. Recurring daily for \>2 hr per day for \>3 months C. Pain has both of the following characteristics: 1. Poorly localized and may radiate beyond the trigeminal nerve distribution 2. Dull, aching or nagging quality D. Clinical neurological examination is normal, however patient may denote paresthesia E. A dental cause has been excluded by appropriate investigations; signs of structural pathology or other specific causes of pain are not identified. Minor operation and injury (insignificant trauma e.g. tooth extraction) to the face, maxilla, teeth and gums without a direct causal relationship with the pain regarding both time and site is accepted. F. Not better accounted for by another ICHD-3 diagnosis. Exclusion Criteria: * Bilateral symmetrically affected * Neurological disorders or other related systemic diseases that can explain the pain * MRI/CT examination confirming intracranial pathology. * Systemic or local disease or condition that can give a significantly increased risk of complications to the particular procedure * Not competent to asses informed consent based on neurological assessment * Psychiatric disorder that prevents the completion of the study * Pregnancy * Inappropriate use of contraception * Breastfeeding * Abuse or unauthorized use of medication, drugs or alcohol * Allergy or other hypersensitivity reactions to marcaine, lidocaine, xylocaine, or adrenaline, possibly similar related drugs * Anatomical factors that prevent or impede the injection * Known hypersensitivity to botulinum toxin type A or to any of the excipients * Treatment with drugs that can interact with botulinum toxin type A: aminoglycoside antibiotics, spectinomycin, neuromuscular blockers, both depolarizing (succinylcholine) and non-depolarizing (tubocurarine derivatives), lincosamides, polymyxins, quinidine, magnesium sulfate, anticholinesterases.