Help! Tempature shocked sea urchin

While doing a water change with R.O. Water we had to risk it and put in cold water so while i chased off the fish from the cold water stream mom dumped the water in, but we didnt know my rose sea urchin was under a rock, its now sort of frumpy, it hasnt moved in a few hours and is kind of on its side, however its still moving its little quills around so i know its alive please help!

Ps its a Sixty five gallon aquarium.