The condition is called “Pericoronitis”. It means, a flap of gum is over the wisdom tooth ( called Operculum) which pains because that flap of gum comes in between the teeth while biting.
As shown from the picture, your wisdom teeth is also placed a little towards cheek ( bucally ) which means it’s “Impacted”.
Treatment options-
1. Apply pain relief oral ointment on the flap of gum ( operculum).
2. Visit a dentist for - a) operculum removal. It will temporarily relief pain.
b) discuss the tooth removal options with dentist and make up your mind for tooth removal.
3. Don’t take too much stress. It’s one of the most common issues with wisdom teeth. They are usually impacted.
But yes, kindly get the operculum ( gum flap over teeth ) removed, otherwise it will lead to infection and more problems in future.
Next Steps
Dentist visit is a must for the solution of your problem.
Health Tips
Avoid biting from left side, till you visit your dentist.