My dog had a abscessed tooth removed about 6 months ago. She started draining yellow "stuff" from her nose. I am on the 4th round of antibiotics. She has extreme difficultly breathing from her nose. She "snores" or makes lots of loud noises trying to breath through her mouth. My vet does not have a scope to see if anything is going on in her nose. X-rays show nothing is there. Does any one know what could be wrong?