As reported by TMZ:
"Tiesto was supposed to play a show last night in San Jose ... but whacked his head on the LED as he made his way to the stage -- and went down HARD ! According to reports, the DJ tried to play his set anyway -- but management said no.Tiesto updated his fans a few hours later saying he got a a couple stitches and doctors said he suffered a concussion."
Here's the video:
I hope for a speedy recovery Tiesto!