Hello,
Thanks for posting your query and my apologies for the delay in response.
From the picture, it seems to be a wart. A wart is a viral infection and needs to be treated as it can spread.
The best treatment for warts on the sole is application of salicylic acid n lactic acid solution on it each night. You need to apply it only on the affected area.
You will require a prescription for the solution and is best applied under the guidance of your dermatologist.
Please let me know if you have any queries.
Take care.