Concise answer
Shock loss describes shedding of existing hair after procedural stress. It can be temporary, but weak miniaturised follicles and donor trauma need individual assessment.
It may occur near the recipient area or, less commonly, in a donor area that has been stressed.
The pattern, timing and condition of the scalp matter more than the label alone.
When evaluation may help
Ask the operating surgeon to review unexpected density loss, especially when it is sharply patchy, painful or associated with skin change.