hello and welcome to health care magic,
I am Dr Sriram Nathan an ENT surgeon and I will try to help you out with your problem.
At the onset let me tell you that
bad breath can have many causes of which
post nasal drip due to
sinusitis and reflux are the commonest excluding dental problems of course.
You need to consider both into your diagnosis and proceed as follows:
1. Take steam inhalation at least three times in a day for the next week with menthol
2. Take a course of antibiotic like amox-clav along with levocetrizine in consultation with your doctor.
3. take also a course of anti
reflux medication like
pantoprazole in consultation with your doctor
4. Avoid spicy, oily and high flavored food
5. If you do not get better then you must take an upper GI endoscopy along with CT PNS and get back to me of any ENT with the report
hope this helps
regards
Dr Sriram Nathan