He got slapped on the forearm by the pass rusher as he was coming forward in his throwing motion. Probably just a temporary nerve thing. Hits like that flash really hard and then subside over time as the nerve recovers.
Wow, this is the worst run defense I've seen in a long time. The Jets D line is being pushed back 5 or 6 yards on every play.
I hope they have to amputate Mike White's throwing arm because it would be the most "Jets" thing ever.