I was a migraine sufferer for many years (they gradually stopped happening, thank Heaven). Going into a dark, quiet place immediately is very helpful, but giving Motrin or any NSAID (aspirin or ibuprofen, etc.) IS CONTRAINDICATED. After the visual disturbances in the beginning when the blood vessels in the brain constrict, usually in response to adrenaline and other stress chemicals, the blood vessels of a migraine sufferer over-react by too much dilation and the result is a little brain swelling and the terrible migraine headache. NSAIDs INCREASE THE DILATION, and make the headache worse.
The reason exhaustion triggers migraines relates to low blood sugar. If a kid w/ an active metabolism exercises heavily or simply goes too long w/o eating or eats only carbs that burn up fast, the body tries to energize by producing adrenaline to help turn body fat to usuable sugar, thus triggering a migraine.
The best treatment I ever found, other than specialized pharmaceuticals w/ side effects, was to put an ice pack at the base of the skull/top of neck toward the side of the head that hurt. That helped shrink the blood vessels back and reduced pain quickly, although it still took a long time to feel mostly normal. Heavy physical activity, like sports, should be curtailed the next day, as the person usually feels drained, and forcing oneself could create a vicious cycle of repeat migraines.
Taking a good magnesium supplement daily, like "Doctor's Best" brand, along with a multi-vitamin helps w/prevention. Magnesium can at first be laxative, so it's best to start out w/ a low dose and work up to ~200mg - 300mg daily divided into 2 doses as soon as the bowels allow. For some people taking magnesium and avoiding blood sugar crashes is enough to end the headaches. Of course for some women nutrients that help level out the monthly hormonal crashes are necessary as well. Highly allergic people sometimes respond to food allergens w/ a spurt of adrenaline, so finding and avoiding foods you're allergic to can resolve the problem.
When you know what to do, migraines are preventable. If the pressures of life lead you into doing something that triggers a migraine, the icepack and/or prescribed medication can be a godsend. Avoid OTC remedies w/ ibuprofen or aspirin like the plague.