Child Has Bad Breath. Had Cold. How Can She Get Rid Of The Smell?

Hi, my 13 year old daughter has had very bad breath for about 2 weeks now. she has never had it this bad... she has brushed her teeth 4 times a day sometimes 5, flosses after each brush, uses mouth wash, and uses a tonge scrapper, but nothing helps... she also has had a cold for the past week and i read about these things called adenoids . i read that they can get enflammed and become large in the back of kids mouth and they also can have a very bad oder sometimes due to nasel issue. we think it might be that because she has been nasel for a week now. if she has this how can she get rid of the smell. we have tried almost everything we can think of. what do you think?