Hello,
For corn of hand, apply lots of moisturing lotion and vit E on the hands. Place protective covering or bandages over the sore to decrease friction on the skin until the sore heals. Rub sandpaper disks or pumice stone over hard thickened regions. Soak feet or hands in warm soapy water to soften the corn. Then rub with a pumice stone and apply some moisturizer.
If still the corn persists, then go in for removal by surgical means or with keratolytic agents (medicines that break up hardened areas of skin). Shaving or cutting off the hardened area on the skin by a doctor is also helpful.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.