Suggest Treatment For Sunburn On Head

my son recently shaved his head and then got sunburnt.. this is normal for him he does this every summer.. took him to hospital, they ran a ct scan, all fluid is around the skull no compression on brain.. they gave him steriods but doesn't seem to be helping..anyway his whole intire head is swollen can sunburn be the cause and what can i do about it??

He is 11yrs and five foot..he has only had flu nothing to bad in medical history..