Not a very clear pic but it may be a wart . You can try some home remedies like rubbing every day with the inside of a banana skin or covering the wart completely with a patch of sticky duct tape. Leave the tape on as long as possible. A week [or more] is ideal.
If you dont have any luck with the home remedies you can buy lots of preparations at the chemist/pharmacy. They can be quite difficult to remove, especially if you have had it a long time but dont pick at it you will make it sore. the treatment needs to penetrate the wart so that it is killed and then will lift off the skin completely,