Luxury line includes zit treatment (5)
I believe the answer is:
ritzy
'luxury' is the definition.
(reminiscent of the Ritz Hotel)
'line includes zit treatment' is the wordplay.
'line' becomes 'ry' (abbreviation for railway).
'includes' indicates putting letters inside.
'treatment' is an anagram indicator (letters treated or processed differently).
'zit' with letters rearranged gives 'itz'.
'ry' enclosing 'itz' is 'RITZY'.
(Other definitions for ritzy that I've seen before include "Ostentatiously opulent (sl.)" , "Luxuriously elegant" , "Ostentatiously rich" , "Luxuriously opulent (slang)" , "Luxurious" .)