Doctor produces dog's dinner to humour handler initially (4,4)

'doctor' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'dog's dinner to humour handler initially' is the wordplay.
I cannot really see how this works, but
'humour' could be 'wit' (synonyms) and 'wit' is located in the answer.
'dog's dinner' could be 'mess' (I've seen this before) and 'mess' is present in the answer.
A single letter 'h' remains which might be clued in a way I don't see.
This explanation may well be incorrect...

'produces' acts as a link.

Can you help me to learn more?