If you are stuck without an abortive, here are some things (taken from another document) that might help:
Caffeine/taurine. For some people, caffeine alone can help to stop an attack or lessen the severity of the attack. Some folks keep strong coffee on hand for that purpose. Some folks use caffeine pills, and some people take taurine pills along with caffeine pills. They take those pills at the first hint of an attack, or a couple of hours before a predictable attack time.
Many use energy beverages. Because some ingredient in energy beverages in addition to caffeine is believed to help with attacks (believed to be taurine), many people use those. I recommend energy shots (such as 5-Hour Energy) at first sign of an attack. Shots are quick to drink down and they have more caffeine than energy drinks, such as RedBull, that are much larger. Many people say the shots work best for them when they are as cold as possible. For many people, energy shots/drinks don’t keep them up even if they drink them at night. In addition to all the “standard” energy beverages, some people like “V-8+Energy” drinks.
“Brain freeze.” You can drink ice water through a straw aimed at the roof of your mouth, with the objective of creating “brain freeze,” or hold something cold, such as frozen juice concentrate, against the roof of your mouth.
Some people find that taking melatonin at bedtime helps (not wise to take both melatonin and Benadryl at night.). Melatonin is depleted in people with CH during their cycles. Some people find that it helps to supplement it. You could start with about 10mg, and go up or down as appropriate. Some people get into the high 20mgs, or even low 30s, before they reach a level that helps. Needless to say, you have to find what works without making you dysfunctionally groggy.
Several people have reported that DMT is an excellent abortive for them. You can read more about that here: https://clusterbusters.org/forums/topic/7444-dmt-first-time-finding-an-effective-abortive/
Feet in very hot bathtub. There’s a theory that this moves blood from your head to other parts of your body. Some people find that putting their hands in very hot water also has an effect on attacks. People have reported that going from feet in a hot bathtub to a cool room and back to the hot bathtub helps the effect. Some people don’t just stand in a very hot bath but will sit or lay in the hot water.
Ice packs help some people.
Cold air. One study showed that inhaling cold air was nearly as effective as using oxygen. Air conditioning vents in the home or the car are good for this. If it’s cold outside where you are, you could try that.
Vigorous exercise. Some people find that vigorous exercise (running; doing jumping jacks, etc.) will stop or slow down a CH attack.
Lime/baking soda. One fellow said that this helped his attacks: the juice of a lime or two along with a teaspoon of baking soda in a cup of filtered (non-tap) water.
Sex. Some people have reported that sex stops their attacks. Other people have been amazed that it’s even possible to consider sex during an attack.