Large dandruff some of them are sticking to the scalp and gives blood upon its removal. what is that and what is the possible treatment?

Possible Infection: Sticky crusts on your scalp(head) are unlikely due to dandruff(dry flakes). There is likely to be an element of infection which can complicate dandruff. You have two choices: it is best to see a dermatologist who can treat you more effectively. if you have difficulty finding one, you can go to any Physician and seek help. In the meantime, use a water soaked towel for 1-Hr/daily to soften and clean