I have had severe migraines since my car accident in 2016 where I also suffered a vertebral artery dissection. So my neck hurting , weather stress triggers my migraines, so the Nerivio feels exactly like the many TENS units I've used over the years. Instead of it being on my neck or shoulder blade it is on my arm basically trying to get my mind of the pain, which it does right after the 45- minute treatment. But on my moderate to severe migraines the pain comes back within 2-3 hours then I just put ice my head and neck. I try to use every other day but without an acute migraine regimen the last 2 days I've used 2 days in a row. I'm concerned if it is actually doing anything. Just want to be honest. Especially for those with complicated migraines like mine.