Mummy? Are you my mummy?

The empty child was a young boy in the boston blitz whos thoughts were altered to be his primary goal by using an alien healing device, His primary thought was who was his mommy. The alien healing device then left permanent healing probes in his body, at the time he was wearing a gas mask so the device thought all humans looked like that and wanted to know who their Mommies were, thus whenever that young boy touched anyone the person was effected the same way, but they literally grew a gas mask out of their face. He and all the others affected by the device were healed when The Doctor reprogrammed the devices to make them the way they were.