Thrush

FTM . I don't exactly know what's that , I just tried to google it , and it made me kinda worried , coz I'm trying to clean my baby's tongue yet he won't let me , I tried to check well his mouth and I see several patches of white on his lips and gums , they said it can be painful, maybe that's why sometimes it's hard for him to suck the nipple 😔 what to do ..?