Reigning on You (2018) online

Media, Pennsylvania is a town with little crime, until October 14th, when college student Camilla Thompson was declared missing. She was last seen at a Halloween party leaving with her longtime crush, Alex. Her best friend, Lani, soon finds out that Camilla was being stalked, getting eerie letters as well as being followed by someone in a mask. Soon after Lani's discovery, Lani is getting left the same notes, and is seeing the same mask follow her around