If my Dad gets custody of me, can I go back to living at my moms?

My dad recently got custody of me and my sister. We wanted to live at ours dads for a while, so we decided to do something about. My dad finally got custody of us and we can see our mom one (1) day a week, and only for 9 hours. I lived with my mom all my life, and now that I am away from her, and been living at my dads for 4 months now, I want to move back to moms. My mom is all for the idea of moving me back in. How would we go along of my mom getting back custody of me, would it be easy?