Used ontop of acne scars along with purito, clashes less with the vitamin c.
(arbutin + centella dream team)
[mainly for vita c in evening if i forgot it in morning]

Used on drier areas on face ontop of moisturiser

Used when not using vitamin C in evening, ontop of acne scars for faster treatment but a very small amount
(careful of silica)

Used for lips only, or if really dry, will put ontop of cream to seal it in (but be cautious if it clogs)