A short prayer to St. Denis to enlist his help against whatever type of headache you are battling.
O God, Who conferred Your saving Faith on the people of France through Your holy bishop and martyr Denis, and did glorify him before and after his martyrdom by many miracles. Grant us, through his intercession, that the Faith practiced and preached by him may be our light on the way of life, so that we may be preserved from all anxieties of conscience, and if by human frailty we have sinned, we may return to You speedily by true penance.
Moreover, I beseech You to graciously grant me, through the merits and intercession of this powerful Helper, the petition which through them I humbly place before You, devoutly saying, “Thy will be done on earth as it is in Heaven.”