New appearance after badly bruised facial feature (8)
I believe the answer is:
sideburn
'facial feature' is the definition.
(I know that sideburn is a type of facial feature)
'new appearance after badly bruised' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'appearance after' says to put letters next to each other (some letters appear after others).
'badly' indicates anagramming the letters (letters in the wrong order).
'bruised' anagrammed gives 'sidebur'.
'n' put after 'sidebur' is 'SIDEBURN'.
(Other definitions for sideburn that I've seen before include "Facial hair grown down one side of a man's face" , "Body hair" .)