I woke up this morning and put on my slippers. I thought something was inside my right slipper but when I looked the bottom of that foot had a ping pong sized soft bulge on the pad beneath my middle toes. As I put weight on that foot I experienced no pain. As I carefully walked around doing my morning routine the bulge decreased (still no pain). I still feel a tiny flat hard spot where the bulge was. So, what was it? Should I expect it to return? It is a danger?
Callosities are usual over the pulps of toes. They are due to overgrowth of keratinized skin due to increased shearing mechanical stress over the skin. If there was no pain, no redness associated with it, I would suggest you not to worry, try changing your footwear to softer ones, But if developed excessive swelling associated with local pain or warmth it is better to consult a doctor in person.