When can i shred again?

4 weeks ago this sunday, i broke my upper left humorous (right below my shoulder) it went into my shoulder cap and dislocated my arm. i went in for my ortho appointment and they took my cast off and i have been moving it around since thursday. i have lost a lot of muscle m so i cant lift my arm up without holding it up with my other hand. i snowboard competitivly so it is imperitive that i get back on snow as soon as possible. its a fast paced sport and when i broke my arm i was top in my division with close followers and im worried i will be ped.i dont need any answers saying " i hope you feal better" or "ask your doctor" i need to know when i can ride again. my doctor said i have an extremely large amount of callusing for 3 weeks (when he told me) and he said i was safe to walk around crowded junior high hallways soo..... i am 12 so he said it will heal fast. my next ortho appointment is after the winter holidays but i need to know sooner than that. thanks.