Was my root c done wrong? Im in pain!!?

Its been like three months since my root c producer and I barely this week noticed I was getting my same symptoms I was having before I had it done. The root c was done in my upper back molar and I had pain that ran though my jaw into the gums and teeth area. I feel it swollen and it hurts I been taking 3 advil every 4 hrs. Since I have a HMO insurance it only covers so much a year and I finished my coverage for the year. I cant afford the dentist right now I dont know if they messed up in the root c has anyone had theses issues?