A Black Spot Appeared On Tip Of Big Toe And

A black spot appeared on tip of big toe and third toe. They really weren't a bother just ugly. After a couple of weeks they were like a callous so I peeled them off and everything was back to normal. Now a few months later it is back exactly like before on the same two toes but the smaller toe hurts to the touch. I am 63 years old, female and have never experienced anything like this before.