The most common and most likely answer to this crossword clue is the 7 letter word WRITHED
I've seen this crossword clue in The Guardian
W
R
I
T
H
E
D
Buddy explains!

The straight part
We know that "manifested embarrassment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case manifested embarrassment = writhed.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 WRITHED mean?
WRITHED verb- To twist, to wring (something).
- To contort (a part of the body).
- To twist or contort the body; to be distorted.
- To extort.