Migraine trigger?

No migraine for nearly a week! What changed?

I thought it very strange that for several days I got a migraine around 7am.

Well, I have a clue. I realised I had woken early with a cracked lip and used some of this blistex relief cream.

It contains Stong Ammonia. Googling Ammonia and Migraines suggests there may in fact be a link.

I am a little reluctant to do a positive test, but having stopped using this I have not had a migraine since.

Update: Bugger - a week with no migraines, then one at 7am. So not that.