Tailor's bunion. To receive an answer that will be more helpful for you, you need to give more information...Your health status, any problems such as gout, diabetes or blood pressure concerns. You should state how long it has been a problem and what you do to make it feel better. Also tells us what it looks like. Is it discolored, swollen or point tender. The more you tell the better the answer.
Maybe a wart. There are several things that this could be. If it is painful when you squeeze it and press on it, it may be a wart. It sould also be a fatty growth called a lipoma. Either way it shoul be looked at by a professional.