As Pebbles' says, if you get a correct diagnosis or they take their word for it that you have CH, then you could suggest something like, "Please check with Up-To-Date or Medscape or whatever service you use, which will tell you that subcutaneous sumatriptan or high-flow oxygen with a non-rebreather mask are the best acute treatments." (Of course, if you've been having an attack long enough that it's still going on after you've gone to the ER and waited to be seen, oxygen might not be very helpful.)
Alternatively, you could print out and carry with you a recent article about treatment of CH, such as this one -- https://pn.bmj.com/content/19/6/521 -- or the Word doc you get from googling [goadsby "treatment of cluster headache"].