A small blotch type which is slightly darker than my skin with uneven sides has come up on my skin and it has grown over the last few days. what is it?

More info.: Dark uneven splotches are typically "age spots", and you're too young for those, so we are going to need more information, or possibly even a photo, if possible. Where is it located? Are there any symptoms (itching, tenderness, etc.)? What do you mean by "coming up" - is it raised, or does it have some sort of texture to it? With more info, we can help you to narrow it down.