He follows the account, showing pain (4)
I believe the answer is:
ache
'pain' is the definition.
(ache is a kind of pain)
'he follows the account' is the wordplay.
'follows' means one lot of letters go next to another.
'the account' becomes 'ac'.
'he' put after 'ac' is 'ACHE'.
'showing' is the link.
(Other definitions for ache that I've seen before include "Long ? pain" , "burn" , "Persistent dull pain" , "Dull prolonged pain" , "Dull continuous pain" .)