The speaker longs for relief from a painful inner state, and the whole poem is built as a series of wishes. It opens with ordinary objects, a switch, a knob, a handle, as if the pain could be shut off as easily as a cupboard door. Behind that door is "cold, red terror" that has "burned so long." The mix of cold and burning makes the fear feel both numbing and fierce. The poem doesn't say what caused it, so we're left with the feeling itself.
The speaker also wants to quiet the "habit of natter," which suggests a restless, chattering mind, and to end an "aching taste of sour." These are small, bodily details that make the distress feel close and wearing. The ending turns softer. Release is imagined as a "smooth satin scarf" laid across a scar, so the hurt isn't erased, only covered with comfort. The mood is weary and yearning, with a hesitant hope. The title, "Finis," suggests the speaker wants an ending.