First I would have to say the pot is too big for the little start of your Christmas cactus
. I would repot it in a much smaller sterile pot with drain holes.
Rinse the roots off well before repotting. IF the roots are "mushy" then it was over watered thus causing the "wrinkling" and you have root rot.
IF the roots are NOT mushy, then it's not been watered enough.
When you repot into a smaller pot, place the starter in the center of the pot.
Water your plant , water will run out, keep watering until the water stays, then don't water again for at least 5-7 days and only if it's dry when you put your index finger in to your second knuckle and you feel dry soil.