Your symptoms of itching, peeling, and a persistent crack suggest a fungal infection (like athlete's foot) or severe eczema, rather than simple dry skin. Since Amirthavennai did not help, I recommend applying an over-the-counter antifungal cream such as Clotrimazole or Terbinafine twice daily. For the deep crack, use a healing ointment containing 10% to 20% Urea or Salicylic acid to soften the skin. Keep your feet clean and dry, and wear breathable socks. If there is no improvement in two weeks, or if you have diabetes, please consult a doctor for a proper diagnosis.