1. Persistent or Returning Pain Ongoing pain weeks after the procedure may suggest infection or inflammation in the surrounding tissues. The pain may be dull, sharp, or throbbing. 2. Swelling or Tenderness Swelling in the gums near the treated tooth, or tenderness when touching or chewing. 3. Pimple or Boil on the Gums A recurring pimple or abscess on the gums called a sinus tract can indicate persistent infection. 4. Discoloration of the Tooth A gray or dark color could suggest internal tissue damage or infection. 5. Bad Taste or Odor A lingering bad taste or odor in your mouth could be due to draining pus from an infection. 6. Loose Tooth A tooth that feels loose may be a sign of infection or bone loss. What You Should Do You should contact your dentist or endodontist as soon as possible. They may take an Xray to check for infection or incomplete treatment and determine if retreatment or another procedure like an apicoectomy is needed.

If the tooth is just a little sore that could be normal, even a month after the procedure. Go back to the original treating dentist for a follow up. For more information you can look at Metrosmiles.com under endodontics

Tooth sensitivity or root canal pain when biting down.
A pimple or boil on the jaw.
Discoloration of the tooth.
Pain from pressure in tooth with root canal.
Tenderness in the gum tissue near where the root canal was performed.
Pain in the tooth you had treated.

Sensitivity to biting or chewing, swelling around tooth , pain in jaw. Similar symptoms as when tooth was originally infected. Recommend seeing your specialist.

Signs of fail root canal would be swollen , abscess or pain still after several months of treatment.