Was prescribed an allergy nasal spray to help with buzzing in ears. How long does it usually take for this to work & can I try anything else?

Probably never. For people with plugged ears, allergy nasal spray may help and the optimal effect is reached between 5-7 days. However most buzzing or tinnitus in the absence of other inner ear involvement, would not be helped by the spray. Often the cause is unknown. Suggest you consult an ENT doctor .