Weird year it has been. Bob went through season and started to headbob all the time when he NEVER did it before, nine years.
Bob has calmed down a lot but will still snap a little. When yours calms back down try this, when he opens his mouth at you put something in it (wadded tee shirt or folded hand towel) and hold it there or pour a small amount of water on his head/in his mouth then continue doing what you were going to. I do this with Bob and he sees that biting won't get him anywhere.