Petrified, X covers up mistakes with deception (6-8)

'petrified' is the definition.
(thesaurus)

'x covers up mistakes with deception' is the wordplay.
I cannot really see how this works, but
'mistakes' could be 'errors' ('error' can be a synonym of 'mistake') and 'errors' is found in the answer.
'deception' could be 'trick' (synonyms) and 'trick' is present in the answer.
'x' could be 'ten' (X is the Roman numeral for ten) and 'ten' is located in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...