Catastrophe!

Showing those photographs may be a retail cardinal sin, but our business plan is to improve everyone's skill set.  Our plants went through that cold snap just like yours did.  Even with a green house, a 200,000 btu heater, and blower fans, we couldn't keep up with the cold.  A lot was composted, but every photo above is of a plant that should bounce back. 

First cut out all of the mushy stems and leaves.  Leave any stem that still firm and greenish, and any leaves that are halfway decent looking.

After you cut the stems back, hopefully you should see some water or sap flowing out of the cut.  That usually means the plant is alive and trying to make new leaves.

The purple part is mushy and dead. Trim below that.

Only the leaves were damage on this plant, the stem seems to have survived intact.

After all the dead and damaged portions  have been removed, put the pot in a bright and warm area and lightly feed them.  They will really need the resources the fertilizer and sun provide to make new leaves. 
After that you should have have a sad looking plant that will grow back bushy and happy!

This applies to  outdoor plants too, but wait to do the trimming until mid February and wait to fertilize until the plant is actively growing.

If the plant is dead, this gives you a chance to try something new!  Keep in mind that these frost swings may be the new normal.  Last year we had a couple days of 0 degrees and one -3!  These are arctic temperatures, and they are lasting for hours at a time.  We didn't carry Indian Hawthorne in 2017 because of those cold snaps and we probably won't again this year.  Watch what doesn't come out of dormancy this spring, these will tell us how we need to adapt going forward.