Red bumpy rash

Hello Anon

Thank you for writing.

You may have a skin infection behind your ears. I think you should also check your hair/skin for lice. While they don't cause blisters, they often begin behind the ears and the itching can cause soreness. It not likely at all to be lice, but do a check anyway.
You will need to see your doctor for a diagnosis but it seems like infection is likely.
Best,
Susan