Hello....  The diagnosis here is definitely a corn,  which occurs in few people with some feet disorder.  Corn cap or some other ointments suggested for such lesions,  usually contains acidic formulations which help in softening the skin.  But as seen in the snap,  the lesion has grown significantly...  Best option right now is to get it excised.  The corn grows inside and keep on pricking as and when u put pressure over it.