Hi CoppersMom, haven't had exactly the same issue, my GSD (no longer with us) once split her nail right down the middle exposing the quick. The nail was never the same after that and continually split causing her extreme pain and lameness. Running would cause the grass and dirt to wedge into the split - ouch! We had the nail trimmed several times at the vet's and finally they had to amputate the toe as the nail never grew out properly again. Hopefully Copper's nail will just regrow like ours do if we lose one. I do think the nail bed and quick will toughen up a bit with time as the nail grows out though and the pain will ease up a bit. Hope so anyhow. Good luck, we're thinking of you both and hope Copper feels better soon.