I sprayed it to the back of my hair, three sprays. I sprayed it maybe ten minutes before leaving the house? I didn’t notice the headache until I had been in my car for a few minutes.
It is possible I started the day out with tension due to the headache, but coming in to work to find unnecessary drama did not help things, that’s for sure. And I reacted in a totally unusual manner in that it bothered me for the rest of the day. I generally let things like that roll off of my back pretty quickly.
The problem lasted all day, too. I sprayed it around 9:15am, and I could still feel the tension going strong about 12 hours later. That’s not to say I think the MX274 was still going strong, but my experience lasted that long.