Extremely entertaining

A fading actress attempts to cling to her youth via black market drugs, with unexpected consequences. This movie starts like a lot of other recent prestige horror films, but gets progressively unhinged in a pretty audacious way, until hitting a climax that goes full Troma (or Gwar).

I liked how it basically follows the pattern of a fairy tale, where something miraculous happens, but with clear rules that have major consequences when inevitably broken.