Yes. Real skin will grow in. But it takes some time. Depending on how big the eschar is, it could take months. The one on my neck took 4 months to heal. I have no experience with the congenital nevi. There is not much you can do to prevent a scar. The eschars are extremely painful. Are you giving the child a baby aspirin or something to ease the discomfort? You are doing the right thing to keep vasoline on it and clean the edges with hydrogen peroxide. Do it twice daily. It will speed healing. Tumeric in the sore is purported to diminish scars, but I haven't much faith in the claim. It would not hurt to mix it in with the gasoline.