Calluses are the most likely diagnosis for the bumps on your foot. They are caused by excessive friction to an area of the foot and result in thickened skin. If the friction is stopped, calluses may disappear on their own but additional treatment with pumice stones or salicylic acid may be necessary to rid your foot of calluses.
However, it is impossible to diagnose your condition without a physical exam. Therefore an evaluation by a medical provider may be required prior to initiating treatment.