With the hair-drying finished, is diminishing (7,4)

'diminishing' is the definition.
The answer and definition can be both related to change as well as being present participle verbs.
Maybe you can see an association between them that I don't see?

'with the hair-drying finished' is the wordplay.
'with' means one lot of letters go next to another.
'the hair-drying' becomes 'blowing' (I am not sure about this - if you are sure you should believe this answer much more).
'finished' becomes 'over' ('over' can be similar in meaning to 'finished').
'blowing' next to 'over' is 'BLOWING OVER'.

'is' is the link.

Can you help me to learn more?