If you broke your pinky finger and it healed broken, can u rebreak it to make it normal again?

Perhaps. When a bone heals in a way that results in a deformity or diminished function, this is called a malunion. Mal meaning 'bad' and union meaning 'healing'. Malunions can be corrected with an osteotmy - the bone is cut, put in a better alignment, and then fixed with a plate and screws or other fixation (depends on the bone). Even after an osteotmy, function in the finger may never be 100% "normal".
Pinky is worst. I find the pinky finger to be the worst finger to break. I say that because it is so hard to keep it from getting stiff and to get it back to the way it was before the break. I would be very very careful of trying to re-break it in an effort to make it better. You may end up doing a lot to try to make it better and have nothing work -- or maybe make it worse. Be careful.