頭懸眼脹 Head Swimming And Eyes Swollen
那師父把頭擡了一擡，又不曾答應得出。行者問：「師父怎麼說？」長老呻吟道：「我怎麼這般頭懸眼脹，渾身皮骨皆疼？」那师父把头抬了一抬，又不曾答应得出。行者问：「师父怎么说？」长老呻吟道：「我怎么这般头悬眼胀，浑身皮骨皆疼？」
逐句解 Line by line
The master raised his head a little, and yet could get no answer out.
應 is yìng here, to answer or respond, not the yīng of ought to. The 得 that follows is the unstressed de of a potential complement — could not manage to get the answer out.
Pilgrim asked, "What does the master say?"
A flat, worried question. Pilgrim is not usually short of words.
The Elder groaned and said, "Why am I like this — my head swimming, my eyes swollen, my whole body aching to the skin and bone?"
頭懸眼脹 is a four-part symptom list of the kind Chinese medical writing favours, and it is describing a perfectly recognisable fever. 皮骨皆疼, skin and bone both hurting, is the aching that comes with one.
Tripitaka gets ill. Not cursed, not poisoned, not enchanted — ill, with a fever and body aches that any reader has had. After eighty chapters of demons this is a startling change of register.
The novel is doing something deliberate. Its hero is a man, and the story keeps insisting on it against all the cosmic machinery. He gets tired, he gets frightened, he cries, and now he runs a temperature and cannot lift his head off the pillow.
Pilgrim's response is the tell. He asks a question in six characters and then, for the rest of this scene, does very little except worry. Confronted with a demon he has a plan within a sentence. Confronted with a sick teacher he has nothing.