I had a nosebleed today with blood dripping down my throat. i has no outward signs. it stopped bleeding on its own. is there cause for concern?

Generally No: Nosebleeds are common and have various causes. Determining the cause will help to avoid them in the future. Commonly finger trauma (nose-picking) leads to nasal bleeds; use a tissue when removing debris. When the mucosa is dry it can easily bleed; use a humidifier to avoid this. High blood pressure can rupture small vessels; control your blood pressure. See your doctor if bleeds do not stop.