My baby is about 3.5 weeks old and we just realized that he has what seems to be a pretty serious lip tie. He’s exhibited very poor weight gain, and his doctor nor the lactation consultants at the hospital never bothered to check his mouth despite having a weird latch/not gaining weight. Has anyone gone through this? What steps do I take to make sure that his doctor takes me seriously when I bring it up at his 1 month checkup? He’s only about 7lbs and his birth weight was 7lbs 1oz so he really hasn’t gained much (he lost 10% of his birth weight almost instantly, and has been slowly gaining back to his birth weight) and I feel like his doctor isn’t nearly as concerned as I am.