A person gets cooler by perspiring. Is this a chemical or physical change?
It's a physical change.
Sweat evaporation is a cooling mechanism that helps keep the body's internal temperature stable in high heat environments or situations.
It is a physical phenomenon because what happens is that water molecules of sweat, when evaporated, contain a slightly higher energy than the average of the substrate, ie the skin. Then, losing energy, the skin cools. There is no chemical change involved, but only a physical process of evaporation of water.