18 items in this article 18 items on sale! Photo-Illustration: Courtesy of the retailer. With warmer weather on the horizon, it’s almost time to switch up your skin-care routine. (Think less moisturizer, more sunscreen.) And if your medicine cabinet could use a bit of a restock, you’re in luck: Dermstore’s Beauty Refresh Sale begins today, and lots of rarely on sale hair, makeup, and skin care products are up to 20 percent off with the code REFRESH. That includes dermatologist-recommended sunscreens for all skin types, our beauty writer’s blackhead-busting serum, and the higher-coverage cousin of Glossier’s Stretch Concealer. (Most of which, we should add, are the cheapest we’ve seen them…