Mostly this wd b ur wisdom tooth which developed a cavity , which u ignored and that increased in such a way that part of the tooth broke
Next Steps
pls visit ur dentist , if its 3rd molar then he will extract it , if its 2nd molar then he wd do a root canal
Health Tips
if the pain is more now, pls take tabs ketorol dt 2 tabs dissolved in water , u will get instant relief