Yes, this is freeze/frost damage on the tender new growth. Hardy plants lose their freeze tolerance once they emerge from winter dormancy and begin new growth, which is why late-season cold snaps can be damaging. Affected plants should recover on their own, and the injured foliage (which cannot heal or return to health) will eventually fall off. In this case, you can probably trim off the damage, but it's fine to wait a couple weeks or so and see where the shrub produces new growth points before you prune. You'd only be removing the dead branch tips bearing brown foliage, and avoiding pruning too far into older healthy growth.

The ongoing drought is stressing many plants, so it would help to monitor the plants for watering needs. If the soil near the roots feels somewhat dry to the touch around five inches deep, the plant could probably use a thorough watering. Expanding foliage takes lots of moisture, so it can be delayed or stifled if the soil stays too dry. (Pieris roots hate staying soggy, though, so that is why the soil should be checked before assuming a plant needs water, to avoid over-watering.)

Miri