Stricken, face turning blue (4,3)
I believe the answer is:
laid low
'stricken' is the definition.
('laid low' can be a synonym of 'stricken')
'face turning blue' is the wordplay.
'face' becomes 'dial' (dial is a kind of face**).
'turning' says the letters should be written in reverse.
'blue' becomes 'low' (I've seen this in other clues).
'dial' in reverse letter order is 'laid'.
'laid'+'low'='LAID LOW'
(Other definitions for laid low that I've seen before include "Stricken" , "Hid away" , "Put out of action by illness" , "Brought down" , "Indisposed" .)