The answer is caffeine is a vaso constrictor. Swollen blood vessels on the underside of top of head result from force trauma trauma that causes inflammation. Caffeine acts to shrink the small vessels in the meninges which would lessen swelling, a component of inflammation, which causes pain Read Migraine Relief Report in Amazon will help you understand better Is a lot of info

I woke up in the middle of the night with a migraine. I made a big cup of French roast coffee and within an hour the migraine was at least something that I could tolerate.

If I have a threatened migraine, sometimes I can stave it off by drinking two or three mugs of black coffee with sugar. This does not always work, especially with a bad migraine, but is my first "go to". If this fails, then I take my triptan and sleep it off.

I have to have one cup of coffee. Each day or I will get a migraine.

If I can catch my migraine before it gets too bad with nausea, I try to have a Coke or Pepsi with some Tylenol. I find that combination with some peppermint oil on my neck and temples has helped a lot!