What's the best way to inform someone that she has messed-up makeup: her lipstick is smeared, her mascara is running or she has a blob of unblended foundation on her face?

Tread carefully when commenting on messed-up makeup. We all have organic markings, whether they are freckles, port-wine stains, burns or scars. Not long ago, I was sitting at the bar of a trendy French restaurant in Cobble Hill (shout-out to Brooklyn!) waiting to be seated for dinner. The bartender who served me had (what appeared to be) a bright pink lipstick "kiss mark" on her lower left cheek. I brought it to her attention only to learn that it wasn't lipstick at all; it was a childhood scar. I felt terrible. I wished I hadn't said a thing, but it was too late. It's not too late for you, however. I consulted with etiquette expert Letitia Baldrige on the finer points of informing someone about their smeared makeup. Here is some useful etiquette advice:

• "If it's not a close associate, don't say a thing," Baldrige says.
• If it's a close associate or family member, "then find a way to whisper to her, where no one will overhear, that there's 'something you might wish to take care of in the ladies' room — a bit of escaped makeup on your face!'" says Baldrige.