If your dog has stopped pulling I don't see how it could cause neck damage?
My spaniel thought a lead meant he should be on his back legs, throwing all his weight against a collar.
I tried dog whisperer style thin collar and lead, some improvement, and choke chain, but both are only useful when used as training aids, to teach them to heel. They need constant adjustment, reinforcement of commands and repositioning of dog. I was walking for hours a day at the time and it was far too much effort. As in cuts and blisters on my hands.
With a halti, I no longer had to keep telling him to heel or fight or spend hours changing direction or pulling in any way, or with treats in my pockets, which only taught him to jump up. Just put dog on lead and start walking (he was a bit fussy at first about having it on his face).
It definitely taught him what I wanted, that walking nicely was the aim of the game. Once this was instilled as the default "what you're meant to do", the Command for heel came in and then went back to choke chain for a while to abruptly correct any times he forgot what he was doing, and now I can't remember the last time I had him on a lead.
It was really tough training that dog, now people say I'm so lucky for having such a well trained lovely dog. Make me cross.