It all depends
Swelling after a root canal
should be a very rare occurence, and should be monitored very cosely.
Antibiotics can be helpful in reducing the swelling, but 3-7 days can be required. You should at least consider that the root canal is ineffective, or did not address the source of the swelling. Request that you be monitored by your dentist that did the root canal or see an endodontist.