The poem follows a man who believes he has pulled off something clever. He has sought safety by dividing himself from something, though the poem never says exactly what. The word "feat" sounds like a boast, but the lines quickly undercut it: fear still haunts him, and his thoughts only multiply.
The poem locates his trouble in "the gap between / what is and what may be," the space where worry grows. Then it turns physical. There is an itch under the skin, and memories of love-making and ordinary pleasures have become nightmares, as if his body has changed from the inside. The poem's phrase is "chemical change in blood and nerves."
The ending is bleak and a little strange. He licks a tulip in the drawing room and acts "thoughtlessly mindlessly," hurting himself further. The mood is anxious and claustrophobic, and the poem suggests that his supposed victory has left him more trapped than before.