Months after the accident, your amputee uncle's phantom limb pain subsides. One

Months after the accident, your amputee uncle's phantom limb pain subsides. One afternoon he is sleeping and you see a fly walk across his upper lip. He wakes up and tells you he just had the funniest feeling. It was as if someone was touching his missing index finger. You decide to experiment with your uncle and you blindfold him. As you touch his cheek he tells you that you are touching his cheek and his missing thumb! As you move around his face you map out his fingers and forearm on his face. Hypothesize how this could be possible.