Picking one's nose can cause upper airway destruction as well as other injuries including nasal septal perforation (a through-and-through defect of the cartilage separating the nostrils), and epistaxis (nosebleed).
They include immediate and severe pain, oozing of blood from the fang punctures, considerable edema, epistaxis, bleeding of the gums, marked hematuria, general petechiae, shock, renal failure and local necrosis.
