
Alec,
Dr. Thomas would need to examine and x-ray your tooth for a diagnosis, but it does seem that your tooth is infected. It is important to see a dentist promptly to relieve your pain and then to re-do the root canal treatment.
It sounds as if the sealer material for the first treatment did not completely fill your tooth, or maybe your dentist did not remove all the infected tooth pulp. But your situation does not mean that your dentist is unable to correct it. If you are no longer comfortable with your dentist, you can get a second opinion.
It is important to see a dentist promptly to prevent the infection from spreading further. And it will continue to spread until a dentist removes it. You can do an online search for an emergency dentist and check their website to see whether the dentist has root canal experience. Otherwise, you can see an endodontist—a root canal specialist—for treatment.
Dr. Siny Thomas, a Sugar Land, Texas cosmetic dentist, sponsors this post.