We're supposed to make sure she gets plenty of rest and "don't encourage her to wag her tail."
Good luck on that proposition! As the proud owner of 4 labs, I can testify that your task is nearly impossible.
Judging from her recent behavior, Swimmer's Tail is caused by dragging miscellaneous deer parts in from the woods to chew on in the yard. They're tail-waggin' good.
I bet she always looks forward to deer season. I hope she gets better soon!