facial swelling after root canal but no pain

Had a crown put on a tooth last month and tried to avoid a rood canal.  The Dentist packed it with something and 4 weeks later all of the sudden started to be extremely sensitive to heat.  No infection detected.  I had a root canal yesterday and I have been taking ibuprofen when needed and also taking garlic supplements just to make sure I don't get an infection but really not having any pain.   My face has gradually swollen on same side this morning and doesn't seem to be subsiding.  Gums don't seem to be swollen, dentist says it may be from anesthesia.  My friend has had 3 root canals and has never had swelling but has had a lot of pain.