AHHA, not true.  I sprayed a dog with bear spray years ago in an ill advised attempt to keep him from fighting with another dog.  When I sprayed both dogs they not only continued to fight they fought harder.  That is when I lost faith in bear spray.  If it wouldn't stop a Brittany spaniel how was it going to stop an enraged grizzly bear?

Anyway, the dog's nose was fine.  He continued to hunt birds until he died.