There's inflammation and it's a bit blue (7)
I believe the answer is:
whitlow
'there's inflammation and' is the definition.
I can't judge whether this defines the answer.
'a bit blue' is the wordplay.
'a bit' becomes 'whit'.
'blue' becomes 'low' (both can mean sad).
'whit'+'low'='WHITLOW'
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for whitlow that I've seen before include "Inflammation of finger" , "Small abscess under a nail" , "Problem to hand" , "Painful inflammation beside nail" , "gathering" .)