You could show it to a private podiatrist. It is best not take risks with your feet, and pay for an opinion from a podiatrist, and treatment. Or, if you are reluctant to pay, the other option is a referral to a NHS podiatrist, through your GP surgery. However, at least in my area, you would have to wait minimum three months. At a guess, it could even be a small corn, but this is NOT a diagnosis.