The most common and most likely answer to this crossword clue is the 7 letter word BOTCHED
I've seen this crossword clue in The Guardian
B
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T
C
H
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More clues leading to the result BOTCHED
Buddy explains!

The straight part
We know that "Made a mess of" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case made a mess of = botched.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 BOTCHED mean?
BOTCHED verb- To perform (a task) in an unacceptable or incompetent manner; to make a mess of something
- To do something without skill, without care, or clumsily.
- To repair or mend clumsily.
- Made or repaired in a clumsy or incompetent manner.