Hello doctor , I have developed a very peculiar skin mass growing or it can be some boil but there is no fluid inside it, seems like dead skin. I have attached the pics. There are three such sights, one is on my finger of leg, which is very prominent nd had been there from long time, the others are recently formed, and one just next to it. And one on the thumb. Please let me know what it is ? How can it be cured ? And the reason of its formation.