These raised red spots are caused by a strawberry - like collection of blood vessels in the skin. (healthychildren.org)
Blood vessels in the skin dilate and heart rate goes up to push blood flow to the skin, where the blood can release heat to cool down. (sciencenews.org)
The raised patches that appear on your skin occur when histamine and other chemicals cause small blood vessels in the skin to leak blood plasma (a watery, straw - colored fluid). (health.com)