The easiest way is to:
a. Put the shellholder with cartridge back into the press.
b. Remove the die.
c. Raise the ram until the bullet itself comes through the top.
d. With a pair of vise grips or channel locks (yes, you're going to ruin the bullet) clamp onto the bullet HARD, and lower the ram. The bullet will separate.
e. Empty the powder, reseat the primer and continue.
Another option is to purchase an RCBS Collet Bullet puller. These work in the same way as described above, but won't damage the bullet that much.
Finally, learn from the experience. Good luck!
Hiding in plain sight...