Maybe rough diamond opposite lake concealed dead skin (7)
I believe the answer is:
cuticle
'dead skin' is the definition.
(I've seen this before)
'maybe rough diamond opposite lake concealed' is the wordplay.
I cannot quite understand how this works, but
'lake' could be 'l' (geographical abbreviation) and 'l' is found within the answer.
'diamond' could be 'ice' (ice can informally mean diamonds) and 'ice' is located in the remaining letters.
The remaining letters 'cut' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for cuticle that I've seen before include "Skin around the nail" , "Skin at the base of a nail" , "layer of protection" , "area of dead skin" , "finger has one" .)