a delayed reaction to the flu shot is a possibility although unlikely but you are definitely having release of histamine with the sore throat
, runny nose, plugged ears and angioedema (swelling) affecting the mouth.
Delayed reaction to mouth washes at the dentist
is more unlikely.
A skin prick or specific IgE blood test
would elucidate if you have any allergies particularly dust mite.
Stopping smoking is a priority (if you do) for several reasons.
Antihistamines such as cetirizine
should suffice (taken one daily for 7 days).
If you are on any blood pressure pills, do get these checked as ACE-i drugs cause angioedema.