Thank you for the query.
in the mouth, need not be necessary that decayed tooth will be the cause for it ,any infection in the gums or bone can also lead to it or tonsilitis
sometimes or viral infections may lead to this condition.
Clinical examination of the area will help in diagnosing the exact cause for the swelling as it could be because of the allergic reaction
which presents with and emergency like difficulty in swallowing , swelling of the face, throat , lip and tongue, difficulty in breathing.
Get back to your dentist
and explain the condition and tell about the drugs you have taken .
According to the clinical examination the treatment plan will be explained to you .
Hope this information helps you.