When you scald your hand with boiling liquid or burn it with a hot object, your first reaction should be to pull it away. Just because your body is no longer touching the heat source, though, doesn’t mean the burning stops.
Layers of skin that were just exposed to a high temperature take time to cool down and a lot of harm can still be done to cells by the residual heat.
Holding burned skin under a tap or submerging it in a bowl of cool (but not freezing) water reduces the temperature quicker, thereby potentially limiting the damage.
Answered by Michael Simpson