I have a very bad odor coming from my right nostrils. I have had a head cold for 2 weeks. Im diabetic, have copd and a bad upper right tooth. I did the research, I'm afraid of brain damage, or meningitis. I have been taken amoxacillin and antihistamines and advil. When should I seek further help.

You need to go to the dentist yesterday. The bad tooth can cause infection which can affect your entire body. Get it fixed now!