If you purchase an independently reviewed product or service through a link on our website, The Hollywood Reporter may receive an affiliate commission. Amazon Prime Day — running from Tuesday, June 23 through Friday, June 26 — is the prime time to save on skin-care staples, namely products from prestige beauty brands that rarely reduce their prices. Exhibit A: EltaMD . In April, the dermatologist-backed sunscreen brand launched the first-ever treatment-focused SPF for acne , its most cutting-edge product to date. The innovative new formula joined EltaMD’s suite of best-selling medical-grade SPFs, each with a deep emphasis on sun care as skin care. Now, the brand is opting into the Prime Day festivities with a four-day discount on most of its best-selling SKUs .…