In Persian we have a saying "صورت را با سیلی سرخ نگه داشتن" which literally translates to:
To keep one's face red(warm) with slap
It's used in a situation in which a person, if poor or unfortunate, tries to uphold his/her outward appearance in a good way in order that others won't notice his/her (financial) issues.
For example: Assume you see your close friend after some time and you realize he is wearing a nice perfume and has put on some flashy clothes. Here is the conversation:
Alice: Wow Bob! You're looking great. Your new job must have paid off!
Bob: Thanks but not really, I'm just keeping my face red with slap.
This suggests that although Bob has financial issues, he tries to maintain his appearance so that others wouldn't notice and his honor would be kept.
I tried searching for an English equivalent but nothing came up. Is there a similar idiom/expression to describe this situation in English?