Hi sir....
The swelling is due to deep cavity that reaches the nerve layer (pulp layer)
First and foremost is to take an x-ray (IPOA)to rule out the exact cause
If tha cavity reaches the nerve layer then Root Canal treatment should be done
Next Steps
kindly visit dentist immediately for futhur management
Health Tips
avoid self mediaction ,self medication gives temporary relief only
avoid chewing at that site of tooth
drink plenty of water gargle with salt water