hello and welcome to HCM From your description it seems that you probably have a case of severe seborrheic dermatitis or dandruff on which you have developed infection. Is is a reaction of the skin where there is excessive oily scalp which increases chance of fungal growth and itching, leading to scabs and pus. It may have been aggravated by hot weather. You will require an antidandruff shampoo (antifungal with salicylic acid) at least twice a week till it reduces. After this continue the shampoo atleast once a week to maintain the results as your skin is prone to dandruff. Over the scabs you may apply a steroid+antibiotic combination cream for a week. Hope these tips help according to your symptoms, but do consult a dermatologist regarding further treatment and to rule out other infections and other conditions which may appear the same way. Avoid oiling your hair or applying greasy or other styling products for now. Hope this helps.