It hurts a little when dissertation edited (5,3)

'dissertation edited' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'it hurts a little' is the wordplay.
'it' becomes 'paper' (I can't justify this - if you can you should believe this answer much more).
'hurts' becomes 'cuts' (cut is a kind of hurt).
'a little' means to remove the last letter (the word is not quite complete).
'cuts' with its final letter taken away is 'cut'.
'paper'+'cut'='PAPER CUT'

'when' acts as a link.

Can you help me to learn more?