Hi Mortartube. I don't know the answer to your question but it sure got me thinking... Older generations in Sweden used the French word mouche (fly) for a "false" beauty mark resembling a facial mole - or resembling a fly that just landed on your face, I suppose. According to Swedish Wikipedia the French eighteenth century aristocracy would apply a mouche to the face to hide syphilitic "blemishes", and it caught on all over Europe - with or without syphilis... Originally they were patches for gluing on, but when they became � la mode they could also be painted on if you had nothing to hide. Again, according to Swedish Wikipedia, you might use the placement of the mouche to send a subtle message: for instance, applying a mouche close to the mouth (think Marilyn Monroe) meant that you wished to be kissed, close to the eye (think Sherilyn Fenn and Dita Von Teese) that you yourself were a flirt.
Any-hoo... the French themselves don't seem to use the word mouche for this kind of make-up? and I don't know if the British do or ever have? But the British word mush for face is pronounced very much like the French word mouche, is it not? As I was googling for "mush" I came across an example sentence which read "I hit him in the mush." Methinks if two aristocrats were fighting it out in an alley, they would surely take aim at their antagonist's mouche...