Ball python can't start shed

[HenryTheSnake]

Humidity should be around 65-75 durring shed.

I understand that, and will have the humidity that high before the next shed. I am buying a humidifier for the room the snake's terrarium is in, because I don't want to put one inside of his terrarium, but what can I do now
to fix the shedding problem?
Thanks,
HenryTheSnake