Agitated by appearance of some white hairs? (3,2)
I believe the answer is:
het up
'agitated' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
(Other definitions for het up that I've seen before include "Overwrought" , "in a state" , "Angry - agitated" , "Indignant" , "in a rage?" .)