I am concerned as a black tongue could be a sign the tissue is dying-not good! THis can lead to infection and could be the reason for the nasal discharge. IThe sooner she is seen the better-as if we aredealing with infection and dying tissue the sooner antibiotics are started the beter before this progresses any further! Not to scare you but some forms of cancer of the mouth can show up in this manner. She's young, so less likely.