Good Morning and welcome. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
Since Sadie did not respond to the medicatoions, there are other conditions that can cause this especially in german shepherds. One is an autoimmune disease such as Lupus which can cause this or Collie Nose which is caused by a photosensitization. A biopsy is required to determine what is causing this so the correct treatment can be given to stop this process.
This LINK will explain in more detail.
This LINK will help also.
get a biopsy of Sadie's nose and this will tell your vet what treatment will cure this.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please Reply so I can clarify for you
Sincerely, Dr. Loretta
You have advised the same as our vet, we have to return this Friday and see what to do next re biopsy