Complex sentence: Vitamin E causes contact dermatitis in up to 33% of users and in some cases it may worsen scar appearance and could cause minor skin irritations, but Vitamin C and some of its esters fade the dark pigment associated with some scars.
Split into simpler sentences: Vitamin E causes contact dermatitis in up to 33% of users and in some cases it may worsen scar appearance and could cause minor skin irritations. But Vitamin C and some of its esters fade the dark pigment associated with some scars.