Oil pulling simply relieves your body from the bacteria that occurs in your mouth, and can affect organs in your system. So sure, it could if your migraines were from a bacteria issue in the soft tissues of your mouth. Heck someone told us once they stopped dialysis after OPing, so I've heard it all now.
Do you have food triggers associated with your migraines? Most are food associated or hormone associated. I'm sure you've been around the block on this, but here are some things for you in case you don't know about them.
Major food triggers seem to be commonly wine, aged cheese, cashews, chocolate, processed meats and caffeine.
I suggest magnesium, B2 and COQ10, Fish Oil and Alpha Lipic Acid.
We all know what magnesium does.
B2 reduces phosphoraylation potential in brain and muscle which suggests a mitohcondiral defect in electon transport. Riboflavin is a percursor for two coenzymes involved in electron transfer for redox reactions.
COQ10, that is also something to take as a precursor.
Neither however worked when the headache had already occured.
The few botanicals I know are feverfew up to 125 mg/day (studies showed amazing results), butterbur 50 mg 3x a day for a month then 50mg twice a day, Valerian at night for sleep (100-300 mg at bedtime, and kava kava which has been found to be good for anxiety and insomnia. Bedtime dose is 150-200 mg 1 hour before sleep.