Hi I just found 2 dark spot in my sons mouth, He is 15 months, 1 spot is hard and the other in next to his tooth . What could it be. I brush his teeth 2 times a day, and he hardly gets any sweets other then natural sugars in fruit and what not. I only found it cause we were playing and his head was tilted back he doesnt seem to be in pain from it. And he hasn t hit his mouth to cause any bruising . I am really worried about what it could be!