Does he get under one's skin? (5)
I believe the answer is:
lance
'does he' is the definition.
'Lance' can be an answer for 'he'. I'm unsure of the 'does' bit.
'under one's skin?' is the wordplay.
I cannot really see how this works, but
'one' could be 'an' ('a' and 'an' can mean 'one') and 'an' is present in the answer.
This explanation may well be incorrect...
'get' is the link.
Can you help me to learn more?
(Other definitions for lance that I've seen before include "Pierce (a boil)" , "Long-shafted weapon" , "Horseman's long weapon" , "Surgical knife" , "Knightly weapon" .)