So technically this doesn't "message" the head. It more so sends little electronic 'shocks' into the muscles, similar to how muscle stimulators recover muscles (you've probably seen physical therapists use these).
Think of a 9 volt battery pinging your head muscles. It's like that. It's not pleasant if you don't have a headache, but if you have a migraine, then you're desperate. The distraction is actually helpful and does in fact ease the pain a little. For my wife--who gets desperate when she has migraines--appreciates having this little device on her nightstand.
Note on the lights: The lights are BRIGHT when it's dark (even with the eyes closed), so it doesn't make sense to use this for sleeping. But for headaches (my wife's purpose), it helps to ease the pain.
Reason for taking a star off: it times out after 15 minutes. My wife expressed frustration that her headache lasts longer than 15 minutes and she kept having to turn it back on.
Original review from Beau Chevassus, Knok Studio (Media for non-profits), http://www.knok.org (Seattle nonprofit) Knok.org
From Beau Chevassus: http://smile.amazon.com/gp/profile/A1IJUCICSBF7LA