Dear madam,
Welcome to practo,
Actually the next tooth also you are having problem so only it has caused pain and swelling.
Next Steps
U should take a radiograph for that particular teeth and then can proceed with root canal treatment. If that cavity is extending towards root or if your bone support of that particular tooth is not good means it should be removed. We can decide the treatment plan with xray.. so kindly take an xray and proceed with medications
Health Tips
Use some warm salt water for gargling
Do brushing twice a day
Gargle after every meal
Maintain oral hygiene in a proper way