Organ lesion would be an unpleasant prospect (7)
I believe the answer is:
eyesore
'an unpleasant prospect' is the definition.
'eyesore' can be an answer for 'prospect' (I have seen 'Ugly prospect' mean 'eyesore' so perhaps 'prospect' could also mean 'eyesore'). I am not certain of the 'an unpleasant' bit.
'organ lesion' is the wordplay.
'organ' becomes 'eye' (eye is a kind of organ).
'lesion' becomes 'sore' (I've seen this in another clue).
'eye'+'sore'='EYESORE'
'would be' acts as a link.
Can you help me to learn more?
(Other definitions for eyesore that I've seen before include "Blemish" , "terrible prospect" , "Ugly sight, not nice to see" , "Hideous building" , "mess" .)