The man who blew off his left arm while setting off illegal fireworks on his Islip Terrace front lawn apparently "knows he messed up." Eric Smith, 36, was using a homemade launcher (a metal pipe) when one hit him in the shoulder on Saturday; his uncle Paul Gilbert said, "He was beating himself up over what he did. He knows he messed up," and also said that Smith's wife "told the kids what happened. But she still hasn't let them see their dad. She thinks it's going to be too much for them to handle." The Post adds, "Gilbert also said Smith has been worried about whether he would be able to work at the LIRR again, but that his cousin, who is a high-ranking railroad official, has assured him he will have a job."