Yea I see the thread is old but hell, here is my 2 cents.
I get migraines so bad that without med pot I would be useless to my family.They are accompanied by severe eye pressure and a partial loss of vision , intense light sensitivity, aggitation, and my eyes go completely bloodshot afterwards.I dont mean, "I just smoked a fatty red", I mean thick red eyes, no whites to be seen.
When I get them NOTHING helps like pot. I have tried lots of pharms but they dont do the job and keep me functional. I got really wasted off of some of the pills they pushed on me and thats just not how I like to be .
I get immediate relief that grows to leave me with a shadow of the migraine that I can sleep off to some extent. The better the pot the better it works obviously.
Pot helps by reducing the pressure in my eyes. Some studies say by 30 % or more.
It takes the edge off and makes me able to dominate the pain rather than cower under it. Anyone who says just deal with it has never had a real migraine.
A less spoken of effect of migraines is the emotional/ psycological one. If you suffer from them you know what I mean. They really get you down and desperate if you cannot escape the pain. They change your lifestyle and chronic ones make you feel helpless. Weed helps with this by lifting your mood and distracting the mind from your pain. It broadens your perspective and reminds that there is life after the pain lol.
So anyway, I dont know the technical ways it helps other than what I have quoted but I can guarentee it works. Downgrading a migraine to a dull throb is a victory if you ask me. Its like downgrading a hurricane to an afternoon rain shower.