Hello, Indentation or callous formation occurs due to extra pressure on the skin, these are pressure injuries. Corn or callus presses into the foot, destroying inner layers of skin and fat and causes cracks, sores or ulcers to form. These open wounds are pressure injuries. Open wounds can cause infection into the body. Extra dead skin may form that is harder. If diabetic, control your blood glucose level at all cost. Get clinically examined by your health care provider or GP. Treatment includes wound cleaning and wound care. Cleaning and disinfecting the callous or ulcer and removal of the dead skin. Antiseptic dressing and antibiotics (oral or i.m or i.v as required). For relieve from pain and inflammation, you can take Naproxen or Ibuprofen, one SOS when required. Give rest to your foot for a couple of days to prevent complications. Use custom orthotics and braces if needed. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician