Septum deviation; the doctor gave me Nasonex, and a wash; it made no difference. What possible reason can it be?

I had a septum deviation surgery in my nose 9 months ago, first few weeks I was able to breathe perfectly fine, after a couple of weeks it came back to normal where I can only breathe from one side of my nose, the doctor gave me Nasonex, and a wash, it made no difference, what possible reason can it be ? Surgery failure ? I do sneeze a lot, and above all when I use otrivin they open and I can breathe really well however I can't use otrivin often only used it once cs it's not good Thank You