My 8 year old son has had headaches quite regularly but becoming increasingly frequent his latest being sunday night to the point it made him dizzy. It eased off but was still present tuesday so I took him drs. Did full range of tests all clear except he suggest slight dehydration but not enough to show on urine test. Said increase fluids and will disappear. He still has the same headache tonight which is not shifting even though drinking loads and taken ibuprofen. Should I take him back to drs?