most common cause of bleeding from Nose is injury to the septum of nose especially near the tip of the nose where it has got rich blood supply, medically this area of septum is known as little's are.
most common cause is self inflicted such as nose picking and sometimes any other type of trauma can also cause this
usually this will resolve once you give adaquate time for it to heal
during episodes of bleeding bend your head and pinch the nose for few mins
consult nearby ENT specialist if your symptoms persists so that he can cauterize the bleeding point