It's located adjacent to the decayed tooth whose root portion is only remaining.
Advised to do salt water gargle 3-4 times a day.
Not to get too worried at the same time do not neglect this either.
Next Steps
visit dentist and get the adjacent remaining tooth root portion extracted.
Health Tips
do not do hot compression/balm or ointment application extra-orally.
quit tobbaço chewing or smoking habit permanently.
consume iron rich foods. as your mucosa appears a bit anemic.
avoid consumption of very spicy hot hard food.