At the Selfie Factory in London's O2, the seven remaining MUAs enter the lucrative world of social media make-up creating fun and impactful looks for the global video sharing platform TikTok. Social media has changed the face of the beauty industry, allowing MUAs to build hugely successful careers on their strong online followings. Joining Val and Dominic this week is guest judge and social media and TikTok superstar Abby Roberts, who found online worldwide fame as a teenager by posting make-up looks of herself from her bedroom in Leeds. The winner of this week's assignment will get to create a video with Abby that will be posted online to her 15 million followers.Upping the ante for their fourth assignment, the MUAs have to grapple with technology as they have just two hours to design, film and create a fun impactful make-up look on themselves, and it must also fit with their assigned backdrop. For their video, the MUAs must film and edit a buildable make-up look to a chosen music soundtrack before their videos are uploaded live on to the platform.The next day, the MUAs gather at Glow Up Studios to find out which two were judged to have created the weakest videos and make-up looks during the TikTok assignment. They both start the day in the red Face Off chairs with a 15-minute time penalty in the Creative Brief. Staying in the online world, this week's Creative Brief sees the MUAs challenged to create a look based on a face filter. They can choose any kind of filter, or they can invent one of their own.The judges deliberate and reveal who will go head to head in the Face Off elimination, a make-up skill drill under intense time pressure. They must create a pop art lip, after which one MUA must pack up their make-up kit and leave the competition.