How to change only the neck of a top to a different color

Select the neck of the top in a drawing program and then paint it with the color you want. Just use the magic wand or lasso tool on the image to select the exact part and fill in the color. You can also paint using the color fill tool or brush. ~~ If you create a new layer and paint on it, you can work while preserving the original image. Nyan~~ (^･ω･^=)~