dental abscess and root canal?

[Ariam]

I have a dental abscess in my front lower tooth.Today was the third root canal sitting. In the second root canal the dentist drained out and cleaned it properly but did not give any antibiotics.The abscess actually became visible from outside. Today he has cleaned it again and cleaned the roots again. However while cleaning it used to pain at times and used to be fine. SO he is thinking that there could be lateral nerves which were not identifiable in the x-ray.However he has cleaned it up real well.He has placed a medication inside the root canal and also punctured the abscess from outside to let it drain.Hopefully it will dry up now.There was no pain prior to the root canal. However today it was pretty painfull inspite the anesthesia especially when he would scrape the root.Anybody has had experience with lateral nerves????