As you can imagine, the comments were filled with some very annoyed fans.
"The mist is the only thing she actually used! This girl basically just spent [two] minutes rubbing her face with her bare hands," one comment read.
"Notice how she never let us see the product on her hands and had to tell us 'okay, I'm using it now' for each product?" said another.
Well, now Millie has shot back at the haters, by reminding them all that she is "not an expert" and is still young in the industry.
"I'm still learning the best way to sare my routines as I get to know this space better - i'm not an expert", Millie's statement - posted on Instagram - began.
"i [sic] thought doing a quick video replicating my personal process for that night was okay, but that's not what was conveyed".
Millie ended by thanking her fans for the 'constructive ctritisism': "i [sic] understand, i [sic] appreciate all of your feedback on this journey, please keep sharing your thoughts and I will too! ily guys x #loveandlight"
Before we continue any further, we'd like to remind you all that Millie is just 15 and new to the industry, so let's all cut her a little bit of slack.
Millie has turned off the comment section on her post, giving nobody a chance to contribute with hate.
The offending tutorial has since been removed from Instagram, according to BuzzFeed News, but it is still on YouTube.
Hopefully, Millie's learnt a valuable lesson about skincare tutorials, because those beauty fans don't play around.