Now that's wild, I wonder what could have happened???
Is his cage near a heater or some kind of electric source?

Yes not to worry about his whiskers, have several with very shorts ones. When they are snuggled up together the whiskers can get in the way of the chin next to them and will get chewed off.
I have one cage with 3 females in it and they sleep the same every day. Well the one who sleeps in the middle has very short whiskers all the time.

She doesn't seem to mind, but just as we see them growing out a bit, they get chewed down again.