The most common and most likely answer to this crossword clue is the 8 letter word GRIMACED
I've seen this crossword clue in The Times
G
R
I
M
A
C
E
D
More clues leading to the result GRIMACED
- Filling in part of puzzle, staff didn't look happy
- I’m aboard; Grace Darling initially pulled a face
- Pulled a face, seeing club surrounded by grating
- Looked disgusted, given ghastly publicity about church
- Stern expert and daughter gave a scowl
- Stern got a good score, and looked pained
- Network admits staff looked in pain
Buddy explains!

The straight part
We know that "looked in pain" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case looked in pain = grimaced.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GRIMACED mean?
GRIMACED verb- To make grimaces; to distort one's face; to make faces.
- Distorted; crabbed