Cannon the picker

Cannon and Bailey both pick at everything! They make a little tiny scratch into a huge bloody gash! So Cannon got a little scratch on the middle of his forehead and before it could even make a scab he was picking at it. We went through a box of bandages and a tube of Neosporin the first week. He doesn't even notice he does it but while he is playing or watching tv or eating would scratch and pick at it until blood was running down his head. Pretty soon his little scratch was an inch round hole! I tried huge bandages covering his forehead, I tried time out when he picked, but nothing worked. Finally Taylor and I wrapped duct tape around his head. He thought it was awesome and said he was a pirate. About half hour later he had gotten it off! Finally I had to stay right next to him for a few days and put Neosporin and a new bandage on every 30 min so it could start to heal. It took a month for that little scratch to heal! Any ideas on how to make a kid not pick at sores?