Puppen Fimo

My Puppen Fimo is too hard! please help!?
It hurts when I sculpt. I usually sculpt with dry clay, but I really want to make something that for a swim if you know what I mean. I'm making a baby doll for my tween sister. And a baby that you can not swim is boring! So does anyone have any ideas on how to soften Fimo Puppen!?
If you're in the clay for a while before you use it, but softens up. (In the box of course!) Warm soft clay = clay. Good Luck!
How to Sculpt Hands in Polymer Clay
