Blood Inmy Phlem Why When You Reach In The Back Of Your Nose Its Blood On Your Finger?

Why when you reach in the back of your nose its blood on your finger? - blood inmy phlem

I suggested a piece of toilet paper, which was called by my nose Enma a finger back preety .. .. ill go lol, but if done befor u do not feel like it's a kind bone in his nose and something feels lyk how this problem .. ex. l (with a small space .. I stopped at this point, but I have blood on my finger, can someone tell me why this is happening or what the blood