A dark area around the root can take several months to heal after re-RCT, so at 3 months it may still be visible. The important thing is whether it is getting smaller over time and whether you have any pain, swelling or other symptoms. From this OPG alone, it is not possible to confirm whether the infection has completely healed.
Next Steps
Follow up with your dentist/endodontist and get a good-quality IOPA of the treated tooth for comparison with the previous X-ray. Usually, healing is assessed over 6–12 months rather than after only 3 months.
Health Tips
An infection seen on an X-ray does not mean you will develop sepsis. If you have no swelling, fever, worsening pain or feeling unwell, there is generally no reason to panic. Seek urgent dental care if swelling or fever develops.