Wondering how everything is going?
If you are looking for a new vet, I recommend trying to find an accupuncture vet. My accupuncture vet, who was 1st trained as a regular vet, takes a holistic approach. The herbs and alternative treatments might be a way for you to go. It sounds like one medication, may just be causing the next problem.
Here's a link to my vet's case study page - the very 1st study is about a Bichon with similar problems:
http://www.apvet.com/case.html
Here's a link to find an accupuncture vet near you:
http://www.aava.org/pub/city.html
It does sound like allegies to something or several things.