Cy tells Chris he should follow scientist Stephen Hawking on social media. The events of the film are just before the school Prom around June 2018 (confirmed by the Principal in the movie), which was approx 3 months after Stephen Hawkings death in March 2018. The film was made in 2017, explaining how this error came to occur.
At the prom Roxy tells her date Chris that she doesn't shave her armpits, and he's fine with that, yet several times she wears sleeveless tops and her armpits are shaved.
When he walks out of the Plastic Surgeon's office, it is clear that the "Free Cosmetic Consultation banner" and "Botox Tuesdays" signs are CGI'd in post. Frame by frame the sign is crisp over the motion blur of the vehicles passing by.