Migraines are largely the result of inflammation problems. We don't know what all the causes are. There appears to be a genetic predisposition, as well as a variety of other triggers such as allergies, chemical sensitivities, etc. But the initiating effect of the migraine is inflammation. For reasons they are still not clear, people who get them experience vasodilatation in their head which causes pain because there is vastly too much blood in your head and the pressure buildup is painful. Basically, constrictions in the blood vessels that allow blood to flow away from your head can cause this phenomenon. We don't know all of the causes for those constrictions or why some people are prone to them and other people are not. But one of the large clumps of nerves that are prone to intense swelling and very near lots of blood vessels in your head, and thus a frequent source of the biggest part of the problem, is in your jaw joints.
There is a dentist who has figured out how to run cold against your gums behind your teeth (effectively through your jaw joint) and reduce the swelling and thus the migraine by allowing pressure to equalize again inside your head.
You can do a phenomenal amount on your own with three ice packs and some elastic to pin at least one to you since you only have two hands. If you put an ice pack on the back of your neck, and one on each of your jaw joints while trying your best to relax all of those muscles, and take a doctor's dose of something that functions as a blood thinner like Advil, and keep those spots cold for at least 15 minutes to allow the Advil to really start to work, you may be able to get rid of the migraine all together.
I grew up getting migraines so badly that I threw up from them at least a couple of times a week. My vision blurred, my day was shot, movement was painful, etc. I wasn't diagnosed with migraines until my teen years, despite having been tortured by them for years. I now have imitrex that I take when I need to, but I have found at times when I didn't have insurance and couldn't afford it, that I could mostly control them.
What I did at those times, was the following: I slept in a nightguard so that I wouldn't be as likely to grind my teeth and thus keep my jaw joint inflamed and under pressure at night. I worked on being more conscious of my pillows and sleeping position to maximize muscle relaxation and circulation. I also found in reading something about stroke victims that there is an insanely high correlation between migraine sufferers and stroke victims later in life. Based on a theory derived from that, I started taking an aspirin in the morning and one in the evening before going to bed. There seems to be a tendency toward blood thickening and clotting that contributes to both problems, and thus for a very similar reason to aspirin helping people at high risk of strokes, it helps with migraine sufferers as well. Those things did a phenomenal amount to reduce the frequency from once a week at least to once a month or so.
When I felt a migraine coming on, as soon as possible, I would take a maximum dose of Advil (4 200mg tabs), a dose of Sudafed non-drying sinus which is a decongestant and expectorant, and two benadryl. I have allergies which contribute significantly to my swelling in my sinuses and such, so that is why I include the decongestant and antihistamine, to eliminate possible sources of swelling. Then I tie an ice pack to the back of my neck, and hold one on each of my jaw joints, trying to relax them as much as I can. I would usually go through two ice packs for every spot to make it all the way to 15 minutes for the drugs to really start having some sort of effect. And then if it was winter, I would deliberately go outside in really warm shoes and as little else as I could stand to be in and still stand out in the cold for 10 minutes or so, even with shivering. If it was summer time, I would take a shower as chilly as I could stand to make it. The cold served to force my blood vessels to contract to keep my body warm, and reduced any swelling that was contributing to the problems.
After 15 minutes of direct ice packs to the worse spots and 10 minutes of overall coldness, usually the drugs were winning and the migraine was almost gone. If I went back inside and was hit by another wave of nausea or pain, I knew it was too soon and I needed to add a little more clothing so I could stand to stay outside, and do so. Whenever possible, I attempted to keep my neck and upper back from being well insulated when outside since that is one of the places where swelling causes the most problems. I probably look silly standing in snow with my jacket on backwards, but it helps a bunch. It was a hell of a lot more low tech than the dentist's gum toy, but it does about the same thing.
One other trick that can help if you find yourself somewhere where you can't do all that, but do have some access to ice and/or hot water, is that if you arrange for one hand to be a vastly different temperature than the other, your body, in starting to try to equalize your temperatures, will start to draw more blood away from your head. When I didn't have anything else available at all, relaxing with one hand in cold water and the other hand in water as hot as I could stand or in a glove or such, would often at least stop the migraine from escalating any further.
Another thing is that in some people, especially people who live in desert climates, a migraine is partially your body's way of telling you that you are very dehydrated. The less water your system has to work with, the thicker your blood will be and the less likely your system will have fluids to flush out calcification and buildup in knotted parts of your body. If you can catch it before it gets to nausea, or if yours don't manifest that way, drinking as much _water_ as you can humanely stand to will vastly improve your chances of getting rid of it quickly.
I hope the suggestions help people. I have generally managed to control at least 98% of mine using those tricks.