When moving plants to less sheltered positions, harden them off in shad or protect them with fabric or a flexible mesh. Plants subject for a long period to tempatures that are too low for them can suffer stem tip damage, scarring or even stem collapse. Rot often than attacks the affected area. Increase the temperature so that dead tissue can dry out. Alternatively, cut out all the damaged tissue.
Healthy growth resumes once the plant is given sufficient light.
Prune affected stems back to good tissue. If starved of water, leafy succulents shed their leaves, then start to die back to the stem tips or shed their branches, and eventually die. Watering usually reverses the process of decline. Cacti shrink into dormancy in a drought but rejuvenate rapidly once watered.