Lip tie experience?

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Does anyone have any experience with lip ties? My son is almost 1 and I noticed he had an upper lip tie almost immediately. I had some issues with his latch and the lactation consultant said it was because he has an over bite (no he doesn't) and not from his lip. I pointed it out to my pediatrician at the first check up and he said it should be fine and they don't usually cause issues. For months I have been struggling to get him to gain weight at a reasonable rate. Looking back at his growth chart, there was a steady decline and he has been at 1% for 3 months. I recently looked up information on lip ties again just to see how it can affect his teeth long term and I saw that in infants, it can cause poor weight gain and long breastfeeding sessions. Well now I'm pissed. Why didn't any of the pediatricians tell me that could be the issue?! So do any of you have babies with lip ties? Did you get them clipped? If they were having weight issues before, did clipping it help with that? I will be seeing a new doctor in a few weeks and will be asking for a referral for a pediatric dentist to see if we should have it clipped now. Thank you for any advice