Panim, which means front, or face, is itself a multi-faceted word. You might have once had your cheeks squeezed, while a Yiddish-speaking relative admires your zeiser ponim, sweet face.
Panim chadashot means new faces. The Sheva Berachot said during the week after a wedding are only recited at a gathering where panim chadashot are present, that is people who were not there the day before. (Talmud Ketubot 7b).The participation of new faces renews the joy of the wedding celebration. According to many, we say the Sheva Berachot on Shabbat even if no new human guests are involved. Shabbat itself counts as panim chadashot.
Panim comes from the verb poneh meaning to turn (ones face) from, towards or away from something. There are a cluster of interesting cognates. Bifnei means in the presence of. Lifnei means before, chronologically, or in front of what is in front of your face. Pnim means inside or innermost, that which is in front of you when you enter. So panim meaning face is almost identical to pnim meaning inside, as if a face is the best way to access what is inside a person.
The Torah is famously described as having 70 panim, different aspects or modes of interpretation.