You know the kind I mean. At the intro of Mission Impossible, we see Tom Cruise, who suddenly hooks a hand beneath his jaw and tears of his face, which turns out to be one of those vinyl masks. Beneathe the mask, he's somebody totally different.
I have seen Mrs Doubsfire, where Robin williams wears one of thsoe masks and can seriously pass for an old lady, and even still has facial mobility. So I suppose it can be done, to a degree.
Given that the guy wearing the mask has a small face, small nose etc, could he really pass convincingly for someone else if he wore a mask?