Would it be worthwhile to pursue legal action for a drainage tube left in my son's leg after surgery?

My son had knee surgery yesterday. He had a lateral release of the patella(?). When he was in recovery before they sent him home, the nurse pulled a drainage tube out of incision site. The leg was wrapped with a bandage that went from his thigh to his ankle. The tube was originally sticking out of the bandage at mid-calf on the outside of the leg. The nurse indicated the site where the tube went into the leg would clot and stop bleeding. A few minutes later as we got him dressed to go home, I noticed blood coming from the site where the tube had been removed. Keep in mind, he had knee cap surgery which required two small incisions on his knee. I asked if there was an incision on the side of his calf since it was bleeding there. The nurse replied, "yes, it will stop with pressure". She got some gauze pads and held pressure on it for a couple minutes. It didn't seem to really stop. The doctor happened to walk by and the nurse asked what she should do. He replied, "wrap it up."