Can you find a different vet? One that is open to listening, consulting other vets and learning ....
There are more effective antibiotics, depending upon the problem.
And doxy + baytril is much less effective then the combos I mentioned.
I have a bronchodilator as a puffer from a pharmacy by prescription from my vet ... this is not as stressful as a nebulizer
What does the vet think is wrong ... ie swollen face and green discharge?