White thing above the tongue

Can it be wiped away with a damp cloth? If it cannot be wiped away, don't use force as it may be thrush (it may bleed). Below may help: https://www.healthline.com/health/baby/how-to-clean-baby-tongue

Hmm a bit hard to tell what it is based from the photo. Best to ask your doctor if this is affecting your baby's eating pattern too.