Note: technically this is against forum rules ("Due to their potential health hazards, we will also not help you prepare your own medicines or cosmetics."). I will leave it for now though, as long as we discuss properties and ideas, not the recipes.
A lot depends on the role of the ascorbic acid in the product. If it is a biologically active ingredient, there is no way to replace it. You may have a bit more luck with finding a replacement if it is there to stabilize pH (with pKa around 4.1 and pH of skin care products starting at 4.5 that could make some sense, especially as ascorbic acid is rather well tolerated).