I remember watching the end of this as a child probably before 1970 on TV, only remember it a bit. People walking out of a fog/mist/smoke from a small town all covered with bumps and blisters. I don't know if it was B/W or Color, because back then the TV would have been B/W anyway.
Possibly "A Feasibility Study", Outer Limits (original series) season 1, episode 29 (1964), in which an entire neighborhood is abducted unawares and placed on a mist-shrouded planet. Humans who contact the aliens become covered with hard blister-like concretions. Plot summary from Wikipedia:
The inhabitants of a six-block suburban area are abducted one night by an alien probe, using a means of teleportation to transport the entire neighborhood to another planet, Luminos. The intention of the Luminoids is to study the feasibility of enslaving the human race for manual labor on their planet, since Luminoids themselves suffer from a genetic disease which condemns them to become as immobile as rocks as they age. Initially, the humans are not aware they've been kidnapped, as the neighborhood appears normal. But a thick fog blankets the area, and the sun doesn't rise when it should.
Eventually, one of the group is introduced to the Luminoid rulers, who are a hideous sight to behold. They make clear what their plans are and the punishment for disobedience, which is to be touched and contract the terrible disease.
The abductees now realize they're trapped with no chance of ever returning home. They come to accept the fact that their lives are over. Full submission to the Luminoids cannot protect them from inadvertent infection. All that's left is defiance and the will to protect the rest of humanity. Forming a circle, they willfully contract the disease from one of their own party, making clear that mankind will choose death over slavery on Luminos.