OH MY !! It looks to me as if your plant has been sunburned.
here is some information that I have found.
â—¾Take the plant back inside and put it in a bright area
â—¾Lay off the water
â—¾Cut the bad, burnt or torched leaves off
â—¾Keep the soil moist but not wetâ€¦ Roots could have become damaged from the heat. Any extra moisture can cause the roots problems. (root rot)
â—¾DO NOT ADD ANY FERTILIZER!
Be prepared for a long wait before your plant comes back to health. It all depends on how bad the plant was damaged.
If after a long while it does not come back, as you would like, you may have to consider getting rid of it. I myself lost several holiday cactus
by setting them out in the direct sun.(on the west side of my house).
Unless one is using a shaded protected area, I think it is best to set out a plant in stages to acclimate it to its new surroundings.