Whine about beginnings of small, tender and unsightly pimple (7)
I believe the answer is:
pustule
'unsightly pimple' is the definition.
'pustule' can be an answer for 'pimple' (thesaurus). I am not sure about the 'unsightly' bit.
'whine about beginnings of small tender' is the wordplay.
'whine' becomes 'pule' (I've seen this in another clue).
'about' indicates putting letters inside.
'beginnings of small tender' becomes 'stu' (I can't explain this - if you can you should give a lot more credence to this answer).
'pule' placed around 'stu' is 'PUSTULE'.
'and' is the link.
Can you help me to learn more?
(Other definitions for pustule that I've seen before include "An infected pimple or blister" , "Let us up, having infected pimple" , "Let us up, having blister or pimple" .)