Tan spot on face, chloasma, nuvaring, 8 months post partum

I have a small (smaller than a pea) size brown (kind of tan) spot on my face. It is round but one side looks moth-eaten . It looks like a patch of brown dry skin . It is VERY VERY slightly raised (can only tell when I rub my finger over it a couple of times and really concentrate) I went to my family doctor on Tuesday and was told that it is Chloasma . I am 8 months POST PARTUM and didn t have any spots during my pregnancy. I am on NuvaRing now and was told it could be due to my contraceptive. Anyway, all of the pictures on the internet of Chloasma does not look like what I have and all seem so much bigger and spread out and this is just one spot (although my skin is extremely dry right now). I have an appointment with the dermatologist on monday as I m worried about this spot...just wanted some information or some experiences?