Colour might show up worsened dermatitis (6)
I believe the answer is:
redden
'colour' is the definition.
(I know that redden is a more specific form of the action colour)
'might show up worsened dermatitis' is the wordplay.
'REDDEN' is hidden back-to-front within the letters.
However, I'm uncertain how this is indicated.
Can you help me to learn more?
(Other definitions for redden that I've seen before include "Evaluate the nature of (something)" , "Flush, become embarrassed" , "Blush or become flushed" , "Blush like the dawn sky" , "Reveal embarrassment in colourful way" .)