You've got a bent piece of stock now, best to replace it with a fresh piece. Watch this video to see what happened (in a bigger scale):
You need to either clamp max RPM really low, or figure out a SAFE way to stabilize the bar. The guy in the video didn't...
If you were holding the bar entirely in the lathe and had the bar slip out of the jaws during facing, you were asking too much from the "system", and need to figure out a different way way to stabilize the part, either with a steady rest or something else. Perhaps face close to the chuck, drill a center hole, then extend and use a live center in the tailstock for additional processing.