A re root canal is required only when the earlier root canal is not done properly or since the crown in this case was not done, the root canal leaked and reinfection was caused.
Request you to get it checked with your local dentist asap, also this time around please get a crown/cap done on the root canal treated tooth to avoid such instances in future.
Next Steps
Get it checked with x rays, get a refillimg done followed by a crown/cap
Health Tips
A root canal tooth always has to be followed by a strong restoration with a crown/cap.