Hi, thanks for your query.
As per your description it seems to be scalp psoriasis
or severe seborrheic dermatitis
You may do as follows:
-use a tar based shampoo every alternate days to wash your scalp.
-apply a mild steroid lotion twice daily for a week or more.
-savlon cream may cause irritation so it is not recommended.
-a short course of oral antibiotic may be helpful.
-take oral anti histamine
If it does not settle in a week or increase, you may consult a dermatologist
for other medication like oral tretinoin.
Hope this helps you.