Small depression (4)
'small depression' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dent that I've seen before include "Hollow caused by a blow" , "Slight hollow" , "Tend to make small depression" , "'Dinge, depression (4)'" , "TV lexicographer?" .)
(Other definitions for pockmark that I've seen before include "injury" , "Pit or hollow (originally in the skin)" , "Scar left by skin swelling" .)