Possible Clues:

• If Sid were to come back with hair like this, he'd be in trouble
• Nervous tension: son's torn out hair
• Headlock?
• D is enough to make the hair be in trouble
• Lock casual worker away from femme fatale
• For this to be on ahead it must be strong
• Highlight holder
• Lock that cannot be opened
• Item saved in a locket, perhaps
• Is it for this that one gets a strong hold on the head? (5)