I was in pain after i was almost finished with the sittings for my root canal. one morning, the pain went away. now, i havea big red lump on my gum and it throbs from time to time.what should i do?

Normal..: The treatment itself is prone to have complications. If it's not finished, wait for the final result. If hurts, your dentist will prescribe the necessary medication.

Still infected: You are out of pain only because the abscess has fistulated, and draining. It then doesn't hurt, but you still have infection going on. More treatment is needed.

Root Canal: You need to finish the root canal and restore the tooth. The bump on the gum is the infection draining and the only way to cure the problem is to finish the root canal and restore the tooth. Please see your dentist or dental specialist asap.

Possible infection: There is also the possibility of a fractured root. Please contact your dentist to have him/her evaluate the tooth.