I have never heard a chick say that about any guy before, I don't know what kind of chicks your hanging out with, but this is what I would have said. My under bite does suck, but you know what your cute except you have a big nose, your boobs are to small, and your teeth just aren't white enough for me, so I recommend getting all that fixed and then come back and talk to me. You might make her cry but oh well she will learn her lesson, and realize that she maybe pretty but she sure isn't perfect.
I have an overbite, and I've been told that I'm cute. There's a LOT more that females look at besides teeth! From my experiences, they seem to be drawn to other facial features, like eyes. Even people with minor aesthetic "flaws" are often seen as attractive.