Keesha's friend is giving a speech tomorrow and is worried because she just got an unflattering haircut. She is convinced everyone will stare at her bangs and will discuss her unattractive hair. Her overestimation of people's reactions is known as:

the spotlight effect.

Explanation:

The spotlight effect is a tendency to think that people get noticed more often than they really do. It is an overestimation of the situation regarding the concern of getting observed. It concerns the self-confidence of an individual. For example, an individual feels that everybody in a party would notice him for a bad pair of shoes while in reality, it does not concern them.

As per the question, the overestimation of people's reaction is known as the spotlight effect.