I had skin rash in my hand and in the bottom of foot what it is could be?

i star having that after i take a calcium supplement .|||Rashes affecting the palms of the hands and the soles of the feet are relatively uncommon. It's most likely to be a condition called hand, foot and mouth disease, which is a viral infection causing oral blisters/ulcers, red-edged blisters on hands and feet, and a mild fever. It should fade in about a week and doesn't require any treatment.