He's been nursing it for a while, playing through it, was questionable going into the Titans game but played.
I suffered from migraine headaches for most of my early life and well into my teen years. They just went away as I got older, I still occasionally get some bad ones, but sometimes they are a year or two apart. My mom has problems with migraines, they would leave her in bed for days, they haven't left her but she's able to control the really bad ones so she's at least functional. Cousin has them too, runs in my family.
I'm not in a position to call Harvin a liar, maybe he is, no way for me to know.
Exactly what my mom would do, just lay in bed for a few days until the most recent attack left. It was awful, nothing we could do for her.