For me it's all about potential risk and I assess that on likelihood and history.
How likely is it to happen, how often has anything like that happened.
I'm 60 and rode bikes for most of them . Never been knocked off a bike, rarely ever ever fallen off and when I have I've never injured myself seriously during tens and tens of thousands of miles of cycling. That forms my historical 'data'....ive fallen over more times on ice when I've been walking but you wouldn't wear a helmet as a pedestrian?
Despite people's fears, cycling is actually quite safe...it definitely could be safer but couldn't everything ?...so in my opinion, the risk is moderately low based on the amount of people that cycle against actual accidents.
So no I don't generally wear a helmet. Sometimes I do (more so in the winter to keep my skull cap in place) , depends on how I feel.
I had an accident in a Land rover once where I suffered concussion as a result of falling off it (don't ask
)....that would neither prevent me sitting on a Land rover again or making me think wearing a helmet while doing it would be a good idea.
If it makes you feel safer wearing because of what happened, great...seriously.
But I wouldn't base my decision on that, no offense intended, that's just the way I'd see it. Wear if i fancy it, dont if i dont.
And i hope your neck repairs fully and soon