In the other objects it worked but for some reason in the skirt doesn't. I'm in the paint mode of the UV Map editor.
For viewport painting:
make sure you have selected the correct image in the slot option ( left side panel slot tab)
make sure you have the texture active by selecting it from the drop down menu in your uv editor.
For both paint modes :
make sure your current texture brush isn't the target texture you're trying to paint on. In the texture option for your brush set it to none ( double check and make sure your mask doesn't have the same texture either )