Suggest Remedy For Small Hardened Spot Of Skin In Right Middle Finger

hi! i'm 25 years old man.i found a small hardened spot of skin on palmar side of the right middle finger just above the distal interphalangial joint, for more than a month. no pain or growth. size of a mustard seed.when i tried to peel it off no pain or bleeding.i tried to peel it off with my nails 2 or 3 times.but its still there.what could be it?what can I do?