This is Pink Turtlehead, otherwise known as Chelone lyonii ‘Hot Lips’.  I really like this flower because it blooms in August and September after all the showy summer flowers are done and it’s supposed to be a larval host for the Baltimore Checkerspot butterfly.  Not that I have ever seen a Baltimore Checkerspot in my yard, but you never know when one might come calling!  The second picture shows it alongside my Boltonia Asteroides, which is still going strong.