Ask your doctor for topical steroids i.e. nasal drops or nasal sprays. The older cheaper steroids i.e. betamethasone should work if the newer more expensive ones don't.
They have less side effects than oral steroids as not a lot of the drug will get into your blood stream if you take the prescribed dose in the correct way. (Make sure you fully understand how to use the drops.)
The only issue with the older ones is that you can only take them for a short duration i.e. 7-10 days there as the newer ones you can take for a month or more.