It's terribly sore, doctor, swallowing: worse than before (4,2)

'worse than before' is the definition.
I can't tell whether this definition defines the answer.

'it's terribly sore doctor swallowing' is the wordplay.
'it's terribly' indicates an anagram.
'doctor' becomes 'mo' (medical officer).
'swallowing' indicates putting letters inside.
'sore' with letters rearranged gives 'ores'.
'ores' going inside 'mo' is 'MORE SO'.

Can you help me to learn more?