Hi.. Thanks for the query.. From your description it is very clear that you had a tooth abscess due to deep decay in your tooth. Due to abscess only there was formation of a blister over the gum above the tooth advised for root canal treatment.. Many a times the pus perforates the nasal floor leading to discharge of blood and pus from nose. But in case if there is no active signs of infection present right now, the chances of nasal bleeding due to the tooth abscess are less.. But still my suggestion to you is to get a clinical examination and x ray done by a dentist and get the tooth treated to prevent further decay that can finally end up in tooth loss. If the nasal bleeding has ceased then it is fine otherwise you should immediately consult an Emergency room.. Hope this helps.. Regards.