Hello.
This appears to be a abscess. Any history of trauma or excessive pressure would have caused this condition.
Once the cause is detected it will be easy to treat it.
Moderate attrition is also noticed which is not common in your age group. The reason could be a faulty bite or trauma due to occlusion.
Initially drainage of the abscess would help
Post an xray.... RCT will be performed if necessary.
For this condition not to reoccur..... And if the reason is clinically confirmed due to excessive force and faulty bite.... Orthodontic treatment would be recommended.
Next Steps
a clinical examination is required. would advise you to see a dentist asap.
Health Tips
use dologel- if the pain is intolerable.
avoid spicy food and hot drinks.