It maybe due to trauma or caries in the tooth. You need to see a dentist for consultation.
If it's due to caries or cavity, you can say, get it restored depending upon the extent of caries.
If it is due to trauma/ injury, then no emergency treatment is given unless the tooth is fractured.
*pain killer will provide you with temporary relief, so consult your dentist for permanent solution.
Next Steps
Get a radiograph of the incisors done as early as possible.
Health Tips
Carious or decayed tooth should be restored as early as possible.