What might block promotion after fears exposed (7)
I believe the answer is:
earplug
'what might block' is the definition.
(an earplug blocks an ear)
'promotion after fears exposed' is the wordplay.
'promotion' becomes 'plug' (plug is a kind of promotion).
'after' says to put letters next to each other.
'exposed' indicates the central letters (outside letters removed).
The central letters of 'fears' are 'ear'.
'plug' after 'ear' is 'EARPLUG'.
(Other definitions for earplug that I've seen before include "It keeps out noise" , "silencer" , "Lug blocker" , "affording protection for organ" , "Hearing protector" .)