Just visited the doctor a few weeks ago for this. Doctor prescribed antifungal solution to swish around baby's mouth and cream for my nipples. It's not completely gone yet by now but it has improved. It's prone to come and go but to avoid this basically sanitise items around baby. My baby likes to chew on her mittens and sleep sack arms and those things are fungal breeding ground.
hope this helps... https://sg.theasianparent.com/newborn-thrush-vs-milk-tongue
you can find more info by googling online