The colour sampler tool, shown below, will enable you to select any colour from within your picture space.
Once the colour sampler is selected your normal pointer will change to the sampler target and wherever you touch down with your pen or left click with your mouse the colour will be sampled and will appear as the foreground colour in the colour picker shown below.
In the example shown below the colour sampler has been used to select the colour from the orange dress to the right. If you then hold the alt key down you can sample the background colour as well.
In practical use the colour sampler can be used to sample a colour close by a burnt out area and then that colour used for the repair.