Partway through the story, the protagonist is speaking with a friend. And he stops mid sentence:
I broke off mid-sentence, as I studied the reflection of his back in the mirror. There was a yellow plaster just below his ear
What does the yellow plaster signify in context? My research suggests it would be used to cover some sort of abscess or cyst, but is it associated with a specific disease during the time the story was published (early 20th century Japan)?