Headache treatment methods are described and include providing, an energy delivery device; locating a secondary or higher-order branch of a postganglionic nerve that provides innervation for a patient's head, by identifying a target region of the patient's head that includes the nerve branch; positioning, within the target region, a portion of the energy delivery device; and applying, from the positioned portion of the energy delivery device to the target region, an amount of energy effective to result in a stimulation activity of the nerve branch; and, after observing the stimulated nerve branch activity, delivering, from the energy delivery device to the nerve branch, energy in an amount effective to reduce a headache severity in the patient.