Is it possible to paint(weight painting) a 3D object upon clicking on it in unity while in runtime?

![alt text][1] [1]: /storage/temp/130649-horse.jpg Take this 3D model of a horse head. My objective is to build and app which can draw up a heat map on touch of a 3D model. When keep my finger on the nose of the horse, that area changes from blue-->green-->yellow-->red. Searches with "heatmap" or "weight painting" didn't do much good.