Unfortunately while there is no schedule in general your BP fails to have bowel movement because it was severely underfed using everything to sustain itself and even now while being fed something slightly bigger the nutriment is essentially used to catch up.
At this size you can feed adult every 5 to 7 days.116g, which i think is Lind of small. The pet store was only feeding her pinkies
Once the BP will catch up it will start growing and have more frequent bowel movements however there will still be no schedule but it should be expected once the animal sheds.