Preseptal Cellulitis

Vanessa, I can't thank you enough for pushing me to see my doctor on Monday.  I had no idea how serious this infection really was.  It all started a couple weeks ago with a zit on the bridge of my nose.  Then my eye swelled up along with my nose, forehead and right cheek.  Fun!  Thanks to large doses of oral keflex, the swelling is now about gone, but I've still got a killer headache and my vision is a bit blurred.  Any idea on how long the headache will last?  Physiologically speaking, how does the swelling and infection cause the headache?