師父有救 The Master Has a Rescuer
孫大聖才按雲頭，對八戒、沙僧道：「兄弟放心，師父有救星了。」沙僧道：「是那裡救星？」行者道：「才然菩薩指示，教我告請昴日星官。老孫去來。」八戒侮著嘴哼道：「哥啊，就問星官討些止疼的藥餌來。」行者笑道：「不須用藥，只似我昨日疼過夜就好了。」沙僧道：「不必煩絮，快早去罷。」孙大圣才按云头，对八戒、沙僧道：「兄弟放心，师父有救星了。」沙僧道：「是那里救星？」行者道：「才然菩萨指示，教我告请昴日星官。老孙去来。」八戒侮着嘴哼道：「哥啊，就问星官讨些止疼的药饵来。」行者笑道：「不须用药，只似我昨日疼过夜就好了。」沙僧道：「不必烦絮，快早去罢。」
逐句解 Line by line
The Great Sage Sun brought his cloud down and said to Bajie and Sha Monk, “Set your minds at rest, brothers. Our master has a rescuing star.”
救星 — a rescuing star — is the everyday word for a saviour, as dead a metaphor as "lifesaver" is in English. Here it happens to be literally true: the help being fetched is an officer of an actual constellation.
Sha Monk said, “And what rescuing star is that?”
是那裡 is a question — what sort of, from where — so 那 is nǎ rather than the pointing nà. Sha Monk asks in the dead-metaphor sense.
Pilgrim said, “The Bodhisattva has just now given directions, and bids me go and petition the Star Officer of the Mao mansion. Old Monkey is off.”
教 is jiào in its causative use. The four-character tail joins backwards onto this line.
Bajie, with a hand still over his mouth, groaned, “Brother — while you are about it, beg the Star Officer for a little physic to stop the pain.”
侮著 is the ongoing-action zhe, and 侮 again stands for the character meaning to cover with the hand. 藥餌 is medicine taken by mouth.
Pilgrim said with a laugh, “No physic is wanted. Do as I did yesterday — ache the night through and you will be well.”
似 is fixed corpus-wide as sì. 不須 takes bù before the first tone of 須. The remedy offered is "wait a night", which is easy advice from somebody already better.
Sha Monk said, “No need of all this chatter. Be off, and quickly.”
去罷 takes 罷 as the sentence-final particle ba, not the verb bà of 言罷 — position decides. 煩絮 is wearisome talk.
救星 — a rescuing star — is a dead idiom in ordinary speech, meaning simply a saviour, and the novel brings it back to life by making it literal. The help Pilgrim has been sent to fetch is an officer of the Mao mansion, an actual star. Sha Monk's question, 是那裡救星, is asked in the idiomatic sense and answered in the astronomical one, and neither party remarks on it.
Bajie's request is the passage's joke and entirely in character: while you are up in heaven petitioning a constellation about a demon, ask him for something for my lip. Pilgrim's answer is unhelpful in a way that is also accurate — he did ache the night through and is now merely itching — and it has the flavour of a remedy prescribed by someone who has already recovered.
Sha Monk closes the scene in a single line of eleven characters, as he closed the council on the slope and the quarrel at cockcrow. The novel has settled into giving him this job: he speaks rarely, and almost always to stop his brothers talking and start them moving.