After Assessing the Patient and Identifying the Need for Headache

After assessing the patient and identifying the need for headache relief, the nurse administers acetaminophen for the patient's headache. Which action by the nurse is priority for this patient?

A) Eliminate headache from the nursing care plan.
B) Direct the nursing assistive personnel to ask if the headache is relieved.
C) Reassess the patient's pain level in 30 minutes.
D) Revise the plan of care.