This is Dr. David
I am sorry about your rash.
can you upload a clear jpg photo of your skin so I can better assess your rash.
you need blood test to check for thyroid hormone levels which can affect cause rash
you need blood work to check for elevated WBC counts.
do you have animals in your home? they can contact fleas and cause bites.
you need to check your bed for bed bugs which can cause bites on your scalp.
you need your skin to be checked for scabies as well.