About 5 years ago I treated a woman who suffered from severe migraines. Her husband, a physician who had trained in Scotland called after her session. One of his mentors was a neurologist (this was probably 35 years ago and the neurologist was old then) who specialized in migraine headaches and was well known for his treatment and success. He sat a patient facing a wall. On the wall were two spots a number of feet apart. The patient moved his/her eyes rapidly between the two points and was relieved of the pain. I have found over the past 400 or so patients that about 20% will report a headache. Some of these will be relieved by the end of the session, others after a nights sleep. I agree with Francine that a two day headache probably is an indicator of something else going on but not necessarily something to worry about.