Andrew Huberman· PhD
that sunburn reflects an immune reaction an inflammatory reaction within the dermal layers of the skin so that means the vasculature right those vessels and capillaries they're going to dilate you often times will get infiltration of things like cyto coses which are of the immune system you get an inflammatory respon that's why it's red that's why it's tender to the touch the nerve endings there can be overly activated so the reason why your skin actually feels warm right when you touch your sunburn is because in fact you have an activation of some of the nerve endings at that site as well as the activation of the local immune system properties that give rise to again vessel and capillary dilation it's a wound of sorts induced by excessive sun exposure