It takes a lot out of a plant to give you a gangbuster show earlier in the season, and now it is spending energy trying to ripen seed for next year. Perennial flowering plants can look pretty ragged once the show is over and they need a rest and will come back new and fresh next season. (We also so see the serpentine, snake-like galleries of leaf miners within the leaf layers, which is fairly common and not a huge problem.)
We suggest cutting off the spent flower stems and keeping it watered if we go into a drought. Our print resource suggests that you can cut back the foliage and a new clean flush will grow back after a few weeks.