My son is 12 and has had a half dozen nose bleeds in the last week. He woke up this morning with his nose bleeding. His nose has never ever bled b4.

Epistaxis. Sometimes epistaxis (nosebleed) is mechanical from picking the nose and creates an open sore that bleeds. Another reason is a cold or allergies can make the turbinates in the nose become easily damaged and can bleed over and over. If the bleeding is coming from one side, most likely a blood vessel that can be cauterized. See an ENT.
Epistaxis. Nose bleeds are common in children with allergies or on antihistamines for allergies. The inflammation from this hypersensitivity is often worse with dry air, nose picking, blowing, etc. In the absence of any other abnormal bleeding (little red dots to the skin, bleeding from the gums, rectum, etc.) humidification of the bedroom with or without prescribed nasal steroid sprays is helpful.