Go to a dentist
Chronic and more severe cases of halitosis may sometimes require you to visit a dentist. Sometimes, bad breath can be a symptom of an underlying condition in the mouth like tooth decay or gum disease. In these kinds of situations, visiting a dentist would be best as he would be able to check your mouth, run tests and give a proper diagnosis of your condition. The dentist can also prescribe drugs and any other supplements that would help treat halitosis. The dentist may also suggest any change that might be necessary for your diet and lifestyle.
Conclusion
Having proper dental and oral hygiene is very important to the mouth and even the general well-being of a person. Treat your mouth well, as you would treat any other part of your body. Brush your teeth when you should, stay hydrated, and eat healthily. Bad breath is not a death sentence, it can be cured, as long as you know the definitive cause of it. Once you do and deal with whatever is causing the halitosis, your breath will definitely get better.
References:
[1] https://www.agd.org/
[2] https://www.mouthhealthy.org/en/az-topics/h/halitosis
[3] https://www.ada.org/member-center/oral-health-topics/xerostomia
[4] https://en.wikipedia.org/wiki/Tobacco_products
[5] https://www.colgate.com/en-us
[6] https://www.hindawi.com/journals/bmri/
[7] https://www.womenshealthmag.com/food/a19891629/best-probiotic-yogurts/