I'm with Jugador on this one. I have to call BS.
First off, maggots will not live or breed on health flesh. There are doctors that will use lab raised maggots to clean out festering wounds because once they eat the rancid flesh, they stop feeding leaving the wound clean. Maggots in your mouth or throat would just be swallowed and digested. People tend to believe crap like this because they can picture this happening and of the pure shock value.