Rashes In Full Body, Hurts While Taking Bath, Nosebleed, No Fever. Lupus?

my 27 month old son is having some strange symptoms he has been wanting me to rub his knees all week today after being outside in the sun (loads of sunscreen on) has a red mark across his cheeks and nose and when i tried to give him his bath he screamed like it hurt. the water was barely luke warm. when i took him out he immeadiately got a nosebleed that only lasted about 5 minutes but then during supper he was quiet, dazed not his normal hyper self. i asked him if he felt sick and he said yes. i asked him if he had an ouch and he said yes. i asked him to show mommy where the ouch was and he put his had on the left side of his head above his ear. i asked him if it was his ear he said no. then after supper he lay down on the couch and covered up in a blanket which he has never wanted to do ever. no fever and kinda mottled red rash around the rest of his face, chin , around ears and neck . he is fair and has sensitive skin . i didn t use anything different or feed him anything out of the ordinary. we went to the park and fed ducks today, he did slip as leaving and bang his head on the car bumper but not hard, he didn t cry and mainly fell on his hands and knees. i wonder could this be lupus or should i be that concerned yet?