Thanks for posting your query.
The foul odour from nose may be due to mucous discharge from nose due to sinus infection
Take complete course of antibiotics and analgesics prescribed.
Use steam inhalation frequently.
Avoid exposure to cold
Intake of cold fluids and food items has to be limited.
Get a thorough scaling done by a dentist
Brush and floss your teeth daily.
For further concerns,please do visit an ENT specialist