You have sun poisoning Check for fever get in the shower and take a shower so that the water feels just a bit cool. You will probably blister thge cool water will remove the heat and you will have less damage. You have second degree burns I've had this a few times when younger. this is why sunblock must be used. BTW i'm at the point where im getting melanomas and carcinomas and a lot of precancerous marks . I worked outside for 40 yrs. but the damage is done when you are young. Sun block!!!!
*serious answer* don't worry about it. It happens sometimes.