fake tan

Maggieee
Okay so I have found a problem with fake tan. Last night my cousin put fake tan on my legs, and of course we followed all the steps, from exfoliating before hand to having a shower after a certain time to wash the excess tan off. But when I came out of the shower the tan wasn't there at all, and there are some bits that as tanned and the rest of my legs are still pale. Anyone know why this would happen?