HELP?

Genesis has this white coating on her tongue and also there are these little black spots. The first doctor we talked to about it said that it was thrush and gave us a medicine that we gave to her four times a day, yet and still it didn’t make the coating and black spots go away. The second doctor we went to said it wasn’t thrush and didn’t seem concerned about the black spots either. I should mention that she breastfeeds and we sometimes use a bottle. I haven’t noticed anything on my end to make me think i have thrush so what is it?!? I’ve been searching the internet in a frenzy and cant find anything . I wasnt able to get a picture of her tongue sadly because she won’t stay still😕