Anything in excess is bad for health.I would like to advice you to get consultation with dentist for bad breath as plaque is the root cause of it. & for allergic rhinitis get consultation with physician /ENT SPECIALIST.
Next Steps
get consultation with physician /ENT specialist for the same & dentist for clinical examination & treatment accordingly.
Health Tips
don't self medicate.
maintain oral hygiene by following proper brushing technique is important.
Thanks!