Hi, in my opinion you your headache is because of elevated blood pressure with fever
Take salt restricted diet and do little exercise your BP may reduce.
But your fever with enlarged lymph node
in groin has to be ruled out,
If were your treating doctor, I would suggest anti inflammatory medicine like paracetamol
to reduce fever.
And also suggedt blood test
and urine test to rule out foci of infection.
Depending on the report I would treat you.