My poor dog's nose! (8)
I believe the answer is:
goodness
'my' is the definition.
(I've seen this before)
'poor dog's nose' is the wordplay.
'poor' is an anagram indicator.
'dogs'+'nose'='dogsnose'
'dogsnose' anagrammed gives 'GOODNESS'.
(Other definitions for goodness that I've seen before include "Virtue, rightness" , "Virtue; excellence" , "Boy" , "Virtue, righteousness" , "Exclamation of surprise" .)