My older brother saw me cut myself?

Wow! It's like problem week for me n my brother! Everything wrong I do he finds out!? Well I was in the kitchen n I cut myself cuz this girl from school told me it helps if ur guilty abt something. It did! So I cut myself.. One small lil cut on my finger.. No harm, just a lil blood n a lil pain n it really took away the quilt. But my brother saw n flipped out! He says I've been acting crazy n self destructive all week n that if I don't stop he will go mental! I understand his problems n stresses, he has fatherhood thrust upon him really early to one self destructive n one wildcat teenager! But I was only trying.. N he yelled at me so badly n said some really mean things... How can I make things right?