After wearing the permanent mask, the man's face kept changing rapidly. The groans became screams, the shaking evolved into seizures, and madness took over sanity.
The artist soon realized that it was all a huge mistake, a black dot in his clean history. He had to take measures. As the poor soul gets tormented, the artist quickly collected all his mask master pieces and and burnt them, releasing the shop's curse. The shop swallowed everything within it, the tools, the masks and the unfortunate inside as well, reducing them to nothingness.
Afterwards, the shop continued to exist like nothing happened.