Above the orifice but below the proboscis, in that are two skin flaps. What is that, and why are they at hand?

Why are there two skin flaps, which form an oval shape, below your feeler, but above your lips? Before you're born, that nouns is split. Usually it comes together long before you're born (but not other, hence the occasional cleft lip), and when it joins, it make the thing you're describing.
OH MY GOD! i hold always wondered that lol