How do you get rid of a migraine lasting over 48 hours?

Emergency Room. I would recommend you to go to an emergency room, coz migrane headache may not last that long provided you took some medication for that. We have to rule out others causes of headache such as a bleed in the brain. Having said that migrane headache is easily treatable but recurrence is more common. Talk to your doctor regarding treatment for long term migrane. Take care.
Seek medical help. If u r unable to get rid of the migraine visit an md it could be serious have you been diagnosed with migraine?