You haven't given the history of pain. Doesn't look like an ulcer. Corns usually appear in the pressure bearing surface of the sole. Soft corns can appear in the non pressure bearing areas of the foot but it doesn't seem like that either. It's better to consult a dermatologist first. Sometimes it's just a small cystic swelling which usually subsides spontaneously

Looks like a corn. It is caused due to excessive friction while walking, mostly due to ill fitting footwear or walking barefoot.

This looks like a Corn.