Dear friend , welcome to HCM.
if it is not itchy, it can be from inner osteomyelitis
or inner ear
or skull bone infection
only clear fluid can be CSF (brain fluid ) , but in your case if there was no trauma to the skull, it is less likely.
do you have fever
has the flake / discharge been cultureed for infection?
pl. see an ENT surgeon to get it evaluated. you amy need Xray skull or CT scan
it could be rarely a cyst (fluidy walled cavity)inside.
take care. and keep me informed on your progress. pl. take a few seconds to rate this experience here before yoy log out.