Hi and welcome to ATP.
It appears that there may still be some green stems left. If the stems are mushy and soft, I would suggest cutting them back a few inches at a time until you reach firm viable plant tissue. If the crown and roots did not sustain damage, the plant should recover, but only time will tell. Keep them out of drafts, water lightly as needed, and watch for additional die back.
I do hope they make it, it looks like they were healthy, strong plants before the freezing weather. Good luck.
