bump on tip of nose after getting novocain

[lola]

i had a root canal done on tooth #5... on my way home from the dentist i my cheek and nose still felt numb and on the tip of my nose it felt like i was maybe getting a underground pimple... when the novocain was compleatly woren off i had a painful bump on the tip of my nose that after 7 years has not gone away... ive seen a ent and dermatologist that dont seem to think its anything but cant give me any kind of diagnoses or idea why this all the sudden popped up...