I have never used one on a dog, but know many people who have with great success. I wear a bio-flow wrist band all the time to stop me getting headaches, have done for a number of years now, after the first one broke, I decided it was all mumbo jumbo and I wasn't going to spend another £50, within a month my headaches returned with avengence, because I hadn't had any for a number of years I'd forgotten how bad they were, £50 suddenly didn't seem much.
I hope it helps for your girl.