Hello,

Thanks for the query.

There can be many reasons for your bad nose smell like:

A sinus infection,
Some gum disease,
Tooth decay,
Bad oral hygiene,
Some previous viral infection causing inflammation or damage to the olfactory nerve which is responsible for smelling.

Since you are already using antihistaminics and decongestants,there are chances of having sinus infection.
I would advice you to consult your doctor and get yourself examined and investigated as per his advice.

I hope to have answered your query and any further query is most welcome.

Wishing you good health.

Regards.

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