[QuickSilver]

I'm a big fan of desensitization. It's slow, but it works.

One day, have her sit next to the collar, praise her, and give her treats. Do this for five minutes, once or twice a day. The next day, let the collar touch her (maybe have her lay down and put it on her back), praise her, treat her. The next day, put it around her neck, but don't fasten it. The next day, fasten it just for a second, then praise her to the skies and give her a huge reward. The next day, fasten it for a few seconds, etc, until she can tolerate wearing the collar.