Ask Mr. Smarty Plants

Don't feel that conditions are any different in terms of freeze-back of perennials. In Central Texas, we had the same conditions in January. You may already know what happened; actively growing plants still have water in their upper structure, particularly the leaves. A sudden hard freeze causes that water to expand, bursting cell walls in the leaves, and they quickly turn dark and look pathetic. What made this freeze worse was that it was earlier than we ordinarily expect these conditions, very sudden, temperatures went down very far, and remained below freezing for several hours. A gradual decrease in temperature over a period of time increases the ability of plants or plant parts to withstand cold temperatures. A sudden decrease in temperature in late fall or early winter usually results in more damage than the same low temperature in January or February.

There are 37 salvias in our Native Plant Database, and 3 native to Washington. None of those three, Salvia dorrii (purple sage), Salvia dorrii ssp. dorrii (purple sage) or Salvia dorrii ssp. dorrii var. incana (purple sage), has a red bloom, which we assume a plant called "Hot Lips" is. "Hot Lips" is probably a trade name assigned to some salvia not native to Washington or, more likely, a cultivar. Because of that, it does not appear in our Native Plant Database as native to Washington, but it probably has similar enough characteristics that we can generalize. 

Since we have always recommended cutting salvias back to about 6 in. after the first freeze, this would seem to be the time to do it. The reason we like to leave 6 inches of stalk above the ground is so you know where it is, and don't accidentally pull out the new sprouts in the Spring, believing they are weeds. It seems unlikely that this plant will suffer permanent damage.