I cut myself for the first time and i heard ringing in my ears and my eyes and head blacked out.. why?

Vasovagal: Likely you had a vasovagal reaction. If you did black out, see your pcp to be sure all is ok.

Vasovagal reaction: Sometimes as a response to pain, the heart will slow, the blood pressure will slow, your skin may feel cold and clammy, you feel faint and/or nauseated. This is called a vasovagal reaction. Most people recover in a few minutes.