Is it safe to complete root canal? A cavity was identified under an existing filling. The filling and cavity were removed, and the tooth refilled. 1 month later, excruciating pain, face swelling. Informed by Dentist, root canal required, but first 1 week of Amoxicillin to cure infection. Infection appeared to be clear, with no adverse affects from antibiotic. Dentist started root canal, but did not complete. Placed medication in cleaned out tooth, and refilled. Prescribed another round of Amoxicillan and Vicoden for pain. Started the Amox again, and took a total of 2 1/2 500 mg Vicoden within a two day period. On third day noticed small zit like bumps on torso and middle back, also headaches. Did not take any more Vicoden..Dentist said continue Amox to avoid infection. Continue to have same symptoms on 5th day after start of root canal, and am scheduled to complete root canal tomorrow (6th day after start). My last 500mg Amox was taken today at 6am. After taking I felt very poor, so skipped my noon pill and will not take again. My face is still swollen. My questions are: Is it typical to automatically get an infection after starting a root canal. Is my swollen face a definite sign of infection, or could it simply be the nature of the procedure? Is it possible that I took Amox for an entire week with no adverse affects, and then suddenly have an allergic reaction the following week from the same medication? Should I take a different medication for infection prior to completing root canal. How long after starting root canal is it safe to wait to finish it?