Don't trouble yourself with disease spreaders in cave on the rise
I believe the answer is:
nevermind
'don't trouble yourself' is the definition.
I can't judge whether this defines the answer.
'disease spreaders in cave on the rise' is the wordplay.
'disease spreaders' becomes 'vermin' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'cave' becomes 'den' (I've seen this before).
'on the rise' is a reversal indicator.
'den' backwards is 'ned'.
'vermin' inserted into 'ned' is 'NEVERMIND'.
'with' acts as a link.
Can you help me to learn more?
(Another definition for nevermind that I've seen is " Don't bother yourself, ignore it".)