According to your information, this is a process of root canal therapy.
The dark brown thing you spit out should be your dead tooth nerve. Before, three root canals have died, and the normal necrotic tooth is black and brown
3. You twice felt pain should be the needles that pierced the root canal, indicating that the length of the measurement should be in place, and the root canal was more open.
"The doctor used a needle to insert a hook into the rotten tooth to hook my lower lip, and the other end of the needle stuck on the needle. This is a meter measuring the length of the root canal.
"After a few repetitions, the doctor sealed my hole with white and asked me to go back to the clinic a week later." This is the medicine that disinfects the root canal, usually also needs a week or so to return to examine!
