What are two ways which the body cools itself down when too hot?

Vaso-dilation: blood vessels near to the skin's surface dilate which allows more heat to be lost. This is because more blood can flow through as there is more room in the lumen.

Sweating: the hotter we are, the more our body sweats. Sweat glands release more sweat because heat energy is used to evaporate the sweat, so it eventually cools us down by using more heat energy.