Ice it to bring down swelling and apply pressure, if it doesnt stop bleeding then go to ER if swelling goes down and it snot bleeding I would sya stay home. If you cant get the swelling down then you could have a break or a fracture and I would get it check out.
My brother broke his arm in 3 places when he was 3 and did not cry.
Even if it stops bleeding it cold still require stiches. I cut myslef with an exacto knife a year ago and needed 2 stiches because the cut was so wide. It had stopped bleeding long before I got to the hospital.