It is also some unusual happened that your potato skin can turn to green. The green part on potato skin indicate the presence of toxin. Better you cut out the green part before you peel your potatoes. The green part of the potato actually just chlorophyll, but this chlorophyll indicates that potato has exposed to light where the natural toxin in the potato (solanine) concentrated at harmful levels. So this make we prohibit to store potato on the room temperature, always keep them in a cool and don’t sun light exposure. Solanine is a natural defense mechanism of the potato to ward off fungus and pests. Solanine substance also make the potato bruished and spoil. If you have potatoes with this indication better to discharge them all. According to some reference solanine can be lowered the toxin if heat on the 306 o F or 150 o C, but heat at 212 o F or at water boiling temperature has no effect, so if you treat the tomato like this better cut it out the green part.