Final answer:
The provided text does not contain information about what was written on the back of Eric's appointment card for Charley's Barber shop, and therefore the question cannot be accurately answered from the given excerpts.
Step-by-step explanation:
The question pertains to a specific detail from a story, and that detail is about an appointment card for Charley's Barber shop in the context of the narrative. However, the text provided does not contain any clear reference to what was written on the back of Eric's appointment card. The passages shared from the story revolve around the character of Bernice and her experiences and interactions regarding the decision to bob her hair, but they do not disclose information about Eric's appointment card specifically. Since the text required to answer the question with certainty is not included, we must refrain from conjecture and acknowledge that the complete information about Eric's appointment card is not available in the context provided.