I Had A Dental Procedure Started, Root Canal. The Dentist

I had a dental procedure started, root canal. The dentist placed an apron in my mouth to protect the mouth from debris. The clamps were place to tight against my gums, and a sore developed. I did a rinse with salt water, but the only relief I am getting is when I take Ibuprofen. I don't want to have to keep taking Ibuprofen, but after 4 days I do not have any other relief. How long should it take to heal, and is there anything else I can do. The sore is on the roof of my mouth, left side, last tooth (15).