I have faint memories of a poignant, B&W S.F. movie from the late 50s or early 60s - which may have been British. All I recall is a man dressed in a normal suit, but something had happened to him that made his skin black and puffy, like it was filled with air, and if he touched you, you'd become that way, too. This man was walking around a neighborhood, not trying to hurt people, but maybe trying to return to his home and family. Again, a very faint memory. Thank you!
This sounds somewhat like "Hand of Death" (1962)
Here is a photo from IMDb.com showing the scientist main character after he is transformed by his experimental formula:
Here is the trailer from YouTube. You can see the 'puffy, black' skin at 0:44 of the trailer.