To show one's face; to make an appearance (i.e., go somewhere and be seen or attend an event).
忙しくても、打ち上げには顔を見せてください。
Even if you're busy, please show up at the wrap-up party.
久しぶりに実家に顔を見せた。
I showed my face at my parents' home for the first time in a while.
新人が本社に一度顔を見せに来なさいと言われた。
The newcomer was told to come by the head office and show their face at least once.