This..
But as an aside, i found the quickest way to make them believe i had very real migraines, was one day, when i started getting the pre-warning Aura that one was coming.. instead of doing what i normally do, which is taking my painkillers and going home immediately before it landed.. was to stay at work.. and let them see first hand how fucking god awful mine are.
I get the ones that like to mimic a TIA.. word slurring, brain fog, then aphasia, complete right sided blindness/sightloss, severe pins and needles down my right side, loss of balance, take about 2 hours before i get it all back, then i go into full on post-drome hangover... i frightened the life out of my team and the First Aider.
They stopped taking the piss after that, if i called in with a migraine, or said i had the signs of one coming, they sent me straight home.
I know not everyone can do that.. but its worth it if you can tolerate experiencing one at work.