I should have clarified what allergies

I had referred to sinuses, so I thought it made it known sinus allergies

I do not use it for skin allergies. It is used for kitties who get all stuffed up with allergies.
What I was trying to find out is, if this turns out not to be allergies, and I meant sinus allergies, then I will have to take Mouzer to the vet and I know that for many other of the kitties, Clavamox and Convenia are often both used for nasal congestion. I did forget to mention that Prednisone is also used for nasal congestion - As in for colds and not sinus allergies. And I know I dont want Prednisone for Mouzer. I was not sure if Clavamox and Convenia are safe for the diabetic kitty. I am trying to find out, so that when the vet starts doing what he does, I can say a yes or no on it.
My vet does listen to me and he will do as I ask. I just have to be informed when I go.
Mouzer had two or three depo-medrol shots, I cannot remember if it was two or three, I actually think it was two, and he acquired diabetes because of it. And because it can cause diabetes in some cats, I do not want even one depo-medrol shot for any.
And I should have clarified, I do not trust any vet completely. I have had enough go bad with even those known to be the best vets. I trust the vet I have now because he is the only vet I have ever had that will at least read and listen to information I have to provide to him. He is willing to learn. He asks questions of me on what I have learned, and he says I have helped him with things he did not know. He also admit, no vet can know all they need to know about any one particular subject unless it is cases they deal with on a very regular basis. I like him. He is not filled with pride, like many others I have gone to. It took me years to find this vet.