Just kidding.
Seriously though, it seems that with today's science fighters are able to recover better than in the past.
The guy who fought Edison Miranda got his jaw broken in lik 3 places and had titanium plates and screws and all. Then just a couple months later they were saying he was sparring and then ready to fight again. Thing is that so far he hasn't really fought yet.
The boxer Antonio Tarver had his jaw broken and went on to fight again and became champion.
I guess it would make a difference if you have the best doctors and followed the best therapy and nutrition and recovery program.
I know of a muay thai fighter whom fought with plates and screws in his jaw only a month or so after surgery and he got KOd with one good shot. Maybe not enought time to heal, or a good shot, or both. He fought again and again repeatedly after that, all fights within a month or two of eachother. I've seen videos of him taking tremendous blows on his jaw(heavy punches, shin kicks, spinning back kick right on the jaw, it made me cring knowing what very few people knew about his jaw), but he didn't go down, not only that but he was totally ok. After hearing about this type of injury and seeing it for my own eyes I'm convinced that people can fight on after such injury. Everybody is different though. I'm sure there are fighters out there with the opposite stories, fighters whose careers were over from such a injury.
Mentality must play a major part. If you are worried you will go down or get further injured it must make you more likely to go down or give in. Rather than if you say I'm not going down for nothing or nobody might help you to not give up and react to blows with tenacity rather than fear and worry.
Of course the best thing is defense and not getting hit on the jaw too much. But it is the fight game and you can't expect not to get hit.
Good luck to you Marco S