Part of a skin care routine (8)
'part of a skin care routine' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for serum that I've seen before include "Antidote" , "Amber-coloured fluid in the blood" , "Antitoxin derived from blood" , "Watery part of blood" , "Blood component containing antibodies, used in immunisation" .)
(Other definitions for cleanser that I've seen before include "Scan reel (anag.)" , "Preparation to remove dirt" , "this can remove dirty marks" , "Lotion removing grime" , "Purgative" .)