Might sound kinda dumb, but try dumping a bucket of (ice) cold water on your head.
The trick is to dump all the water at once and not gradually to get your body into a “I’m being attacked by lions!” state.
This is for instant relief. For gradual improvement try increasing your daily water intake - set reminders to drink a glass or two during the day and drink right before going to sleep and right after waking up.
Source: inherited migraines from my grandma and started getting them regularly around my teens.
Doing the above has made me nearly migraine-free except for when there’s drastic weather changes (when I get them with auras and everything 😵💫).
Good luck!