The fact that an already timid dog was yelled at is unfortunate,
but holding her by the collar when you did it, makes it worse
for the dog. The natural response of a scared dog is "flight or
fight" She wouldn't & couldn't do either. Everyone loses their
patience in training/correcting their dogs once in a while, me
included. I hope the time away camping helps in re-connecting
and earning her trust. Would it be possible to "gate" the dog
off from tempting chew things until she learns to ignore them?
Maybe give her more safe chewable toys to occupy her time.
Good luck to you both.