Lab Pup has limp hind leg

[labpup]

Hi everyone. This is my first post. OK, here's my story: My wife and I had been looking to get a Yellow Lab for about 6 months. We were recommended to a breeder about 2 hours from where we live (VA, USA). Long story short, we ended up taking a pup that came out of the womb with a case of Bell's Palsy in it's left eye. We took the pup because we felt sorry for it and also because the breeder couldn't sell the pup so she gave it to us for free which saved us $800 (but the money wasn't the biggest reason). Anyway, the week before we were to pick the little girl up the breeder called and said that the pup had been playing with it's littermates and seemed to have sprained it's back right foot. She took the pup to a vet who confirmed that it looked like it was just a sprain. So we picked up the pup (we named her Honey Bear, aka. "Honey") a week later and her eye looked a lot better but she was still limping a little bit. She seemed to be getting better for about a week then we noticed that her limp got worse all of a sudden and she started to walk on the top of her foot. At that point we started getting worried that it was more than just a sprain. We called our vet and made the earliest appiontment we could (today at 4 PM). Yesterday, she pretty much gave up using that leg all together from the knee down and just drags it along. Though, when she does get the leg underneath her she seems to use it a little. My wife's a Physical Therapist and she did some sensation tests on the leg and the dog didn't respond to any of them which means that she cannot feel anything below the knee. So we're thinking it may be nerve damage and not just a torn ligament, tendon or muscle. Anyway, I just wanted someone to share Honey's situation with and maybe someone's pup or dog out there has had the same problem and can offer some advice or knowledge about the issue. I'll let you guys know what the vet says. Thanks for listening.