Have masks of course on companion, covering over part of face (8)
I believe the answer is:
eyepatch
'covering over part of face' is the definition.
(covering over an eye)
'have masks of course on companion' is the wordplay.
'have' becomes 'eat' (eating is a kind of having).
'masks' indicates putting letters inside (mask can mean to cover up or conceal).
'of course' becomes 'yep' (yep can informally mean yes).
'on' is a charade indicator (letters next to each other).
'companion' becomes 'ch' (Companion of Honour).
'eat' going around 'yep' is 'eyepat'.
'eyepat'+'ch'='EYEPATCH'
(Other definitions for eyepatch that I've seen before include "Pirate's facial attire" , "Optical injury cover" , "socket cover" , "Cover for optic injury" .)