Hairband with minor problem (7)
I believe the answer is:
ringlet
'hairband with minor problem' is the definition.
I can't tell whether this definition defines the answer.
'hairband with minor problem' is the wordplay.
'hairband' becomes 'ring' (I can't explain this - if you can you should give a lot more credence to this answer).
'with' says to put letters next to each other.
'minor problem' becomes 'let' (let can mean an obstruction or hindrance).
'ring'+'let'='RINGLET'
(Other definitions for ringlet that I've seen before include "Curl of hair; butterfly" , "Hair feature" , "A curl - kind of tingler" , "twist of sorts?" , "Curling lock of hair" .)