A message about temperature I had, providing remedy (8)
I believe the answer is:
antidote
'remedy' is the definition.
(antidote is a kind of remedy)
'a message about temperature i had' is the wordplay.
'message' becomes 'note' (note is a kind of message**).
'about' is an insertion indicator.
'temperature' becomes 't' (abbreviation).
'i had' becomes 'id' (I'd).
't'+'id'='tid'
'note' enclosing 'tid' is 'ntidote'.
'a'+'ntidote'='ANTIDOTE'
'providing' is the link.
(Other definitions for antidote that I've seen before include "Counter to a poison" , "It neutralises poison" , "Counter-agent" , "Counteracting remedy" , "Medicine countering a poison" .)