Lump on foot

I had been hiking a good three hours up and down.. I the day after have a bone like lump on top my foot. It is hard and is about the size of a gum ball. It just popped up. What could this be and is it commom to have bones pop out of your foot? It hurt but only hurts not if I touch it. It is above my little toe about three inches up. I go tot he foot doc the 5th of Nov should I be alarmed?
Thansk any advice or help is well appreciated!! Heather