My cosmelan mask seems to be falling off in small patches 3-4 hours after application. Is this normal? (photos)

Hi I got Cosmelan applied earlier today. I was told to sleep with it over night and wash after 8 hours. It has been drying in the first 4 hours and developed a crocodile skin like texture. What worries me is that it seems to be falling off of my face in small patches already and I am sure most will come off if I put me face down on a pillow. Is this normal/ok?