First of all, just to be certain, was there a second appointment for finishing the RCT?
Assuming that there is still an infection on that tooth, there are many options for treating it besides extraction and repeating the RCT, like apicoetemy or root amputation. It depends on the situation.
Hi Dr Daniel, thanks for your reply, yes there was a second appointment. I'll explain the whole thing....in February 2012 I had pain in a molar that already had a filling in. I went to the dentist (reluctantly as I HATE the dentist

) and the dentist said I'd need a root canal. I paid for the root canal, but then the tooth stopped hurting, so I didn't go back to the dentist. I hated the thought of the RCT so I ignored it. In August 2012 I got a small lump on the gum above the tooth. I'm a student and I had a really important exam the following week, I was also on placement in an acute medical admissions facility and was highly stressed. I assumed the lump would be due to stress but I went to the dentist to make sure. I had no pain, was apyrexial etc so I did not think it would be due to infection. The dentist said I had an infection so prescribed some antibiotics then said to return to start the root canal.
When I went back the gum boil was still there and there was still infection there. The dentist drilled through the filling, took out the nerve then put a temporary filling in and told me to wait until the infection cleared. She said that as the infection had been there for months it would take a while to clear. I wanted more antibiotics but she was reluctant to prescribe any. I was convinced that I'd end up with endocarditis or something so she said to go back in seven days and she's give me some antibiotics if it was not draining well. Then the week after if the infection had gone I'd have the filling, then wait a while, if there was no pain then have the tooth capped.
When I went for my second appointment she said there was no sign of infection, so she could fill the tooth straight away, but I was concerned as the gum boil was still there, so she took 3 X rays and said there was definately no infection, then cleaned out the tooth, then filled it. She said if there was still pain the tooth would have to come out.
I'm due to go back in six months to have the tooth capped. But now I'm left wondering if there is still infection in the now sealed tooth. There's the gum pimple still there. There's no pain, but then again, there never was, even when the infection was there I had no pain. So I'm just really unsure. Then on top I'm really worried because it took so long to go to the dentist in the first place because of being scared....in the end I only went cos I convinved myself it could end up fatal

I even almost ended up defferring my exam as I was so convinced something bad would happen.
Sorry this post has been so long and thank you again for your help it is very much appreciated.