|AE12 of Mallos in Cilicia, 4th century BCE|
Luckily for me, I was able to ask for help from the members of the Forum Classical Numismatics Discussion Board. There, I was pointed to the town of Mallos. The PY is actually the beginning of the name of the character depicted, not the town. It is the head of the river god Pyramos. By coincidence, I have recently written about another coin showing Pyramos here.
The reverse of the coin shows a round female face with curling locks looking out towards the observer. This is a gorgoneion, the face of a gorgon. There are many ancient coins with such a face, most of them much more contorted and horrific than this, often with the tongue sticking out. A gorgon's gaze was said to turn its object to stone, so this image was supposed to ward away evil influences.
The gorgoneion on this coin does not seem in the least frightening, and although not everyone likes this sort of thing, I think it has been made even more lovely by the range of warm colours that have developed during its patination.