Raised mark on skin round dry blotchy area (6)
I believe the answer is:
mottle
'blotchy area' is the definition.
(blotchy area of skin)
'raised mark on skin round dry' is the wordplay.
'raised mark on skin' becomes 'mole' (mark on the skin).
'round' indicates putting letters inside.
'dry' becomes 'tt' (abbreviation for teetotal).
'mole' going around 'tt' is 'MOTTLE'.
(Other definitions for mottle that I've seen before include "Irregular arrangement of patches of colour" , "Variegated pattern" , "Let Tom variegate blotchily" , "Colour with blotches of different shades" , "Colour blotchily" .)