This is it!

Ever since I was a kid I remembered a movie I saw on TV about a guy who was impersonated by or taken over by an alien and a scene where he burned his hand till it was black and then rubbed the burnt skin off to reveal new skin underneath, thus protecting his true identity.

For some reason I thought it might be an Italian or other foreign movie. Now that I have seen this movie again I think it's because of Richard Devon's character that I thought this was a foreign film. There is just something about his portrayal that seems more European than American to me.

As for the scene above I didn't realize until my recent viewing that as he is rubbing the burnt skin off his hand that it has no fingernails in one close up shot. When the processed is finished his fingernails are there. Very well done for a Roger Corman film. Compared to Corman's other films this is an "A" production for it's special effects and miniatures.