Being truthful with history

During clerking, patient is expected to be truthful and give detailed information about thier health but often times ,patient hide this information to clinians which can lead to a fetal outcome.
I clerked a patient and asked of drug allergy of which the patient said he does not react to any drug or react to anything.
On giving giving local anaethesiatic agent to help the patient ease pain for the procedure he is to undertake .
When the procedure started we noticed facial swelling which was progressively increasing on everyminute which is an emergency.
Intra venous hydrocortisone was given to control the inflammation and the procedure was stopped .
Antibiotics was also given to control infections on the areas.
We are to be very truthful when we are with our doctors so that optimum treatment is given to us.