These go away in 20 minutes. How does botox for migraines work? Pin On Health And Science It’s recommended to receive botox in the 30’s, when wrinkles are just starting to appear. How long until botox works for migraines . How long does it take for botox to work? This was my first time, i'm relatively active, metabolism is. After receiving botox injections, it can take 10 to 14 days or more to experience relief. Fortunately, some patients who develop antibodies to botox, known as type a toxin, may respond to a similar product myobloc, which is a type b toxin. Some patients do not start to improve until after their second set of injections which is given 12 weeks after the first set of injections. Myobloc is not approved by the fda to treat chronic migraine headaches, but it has a similar mechanism of action and has been shown to relieve migraines in several studies. Anyone with serious chronic migraines knows the pain they will go through for a 50% chance of s...