Does A Deep Wrist Cut With Light Bleeding Need Medical Attention?

My 8 year old son broke a bowl and his wrist was cut. The cut is about an inch long lengthwise but quite deep, the cut just opened right up. I could fit an m&m in the wound.There was not alot of bleeding, in fact, it did not bleed for the first few seconds. The bleeding is stopped, I ran it under cool water and butterflied the cut. Do I need to worry about nerve damage? Should he be seen by a professional?