Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain it seems bad breath and terrible smell from nose and sinus issues seems most probably due to infection in the sinuses leading to Sinusitis and as the sinuses drains through nostrils, there is bad smell through nose.. In case of sinus infection only sinus rinse along will not relieve and a proper treatment has to be taken.. I would suggest you to consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like PNS view x ray or MRI scan can help in diagnosis and treatment can be done accordingly.. You can be advised a course of antibiotics, anti-inflammatory painkiller like Ibuprofen, decongestants like Pseudoephadrine, do saline nasal irrigation, steam inhalation and use a humidifier in your room.. You can also be advised decongestant nasal sprays containing Xylometazoline or Oxymetazoline.. Avoid spicy and chilled foods.. Do warm compresses around nostrils.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.