for about 3 or 4 weeks now, there has been a pimple like dot on my face, surrounded by a perfect circle of skin which is much, much lighter than my own skin tone. this pimple like dot has no pus in it. the dot seems to growly, very slowly; the perfect circle area seems to be staying the same. i'm 20 y/o' otherwise healthy. recently got a cat, if that makes any differenc.