Sun cream for vampires is a quest item from the Game of Crone DLC, obtained during the vampire questline. After gaining a clue to the vampire's identity from the Astrologer and confronting Master Alaric, Alaric will tell you about his intention to stop the Ancient Curse, halfway through which he will faint. Giving him a drop of Blood will revive him, and he will reward you 3× Scroll of teleportation and the sun cream. You can give the sun cream to Horadric as "proof" of the vampire's death, and, after some reluctance, he will reward you with 50 .