Inclusion Criteria:  ICHD-3 criteria for chronic migraine (code 1.3). See Table 3. Older than 18 years and younger than 65 years. Migraine started in their lifetime before the age of 50 years. Migraine of more than one year of evolution since diagnosis. Normal cranial CT/MRI study. Indication for treatment with Botox Taking triptans as a rescue treatment for migraine attacks  Exclusion Criteria:  Pregnant women Migraine of less than one year of evolution since diagnosis. Pathologies that contraindicate the use of OnabotulinumtoxinA (myasthenia gravis, myopathies).