BTDT with my first, and it was HELL!!! The ped and hosp. nurses gave me the same line--no big deal, most kids outgrow it, it would only possibly be a problem maybe when he starts to learn to talk,

But by 3 weeks, my nipples were shredded--no exaggeration. My right side didn't even look like I HAD a nipple, bleeding, major pain, etc. TBH, that nipple still is deformed, although it seems to work okay. It's weird looking and takes more work (for me) to help them latch on well. I guess it's just scarred.

Thankfully, I had a friend who helped me find a good LC, and she really went to bat for me. She gave me lots of info, and even ended up calling our Ped (who was saying it wasn't a big deal, because ds was gaining weight just fine, so it couldn't be a problem) and begging/demanding that they give me a referral to an ENT.
We finally had his tongue clipped at 3 weeks, and the very next time he latched on, I felt SUCH an amazing difference! Immediate! Even though it still took 2 more months before I was completely healed (because of how bad the tissue damage was), I could tell from that first feeding that the damage was not continuing, if that makes sense.
Also, because ds's latch was not effective, my milk took a long time to come in. Five days before I had any milk, and more than a week before I felt like my breasts were "full". And he was nursing 40 minutes out of every hour. Seriously. Less than that, he prolly wouldn't have been gaining weight. And of course, with that much CONSTANT nursing, the damage to my nipples was that much worse.
I also think that I may have never really had a great supply with him, due to not getting a good start. I always noticed a big drop anytime I got sick, or stressed, and definitely (after my cycles returned) when I was ovulating. It just seemed like my supply was always in jeopardy, something I always had to be super careful to protect.
Anyway, we managed to nurse until he was three (through pregnancy, and tandem for a year!) but I just know there's no way we could have persevered without having the frenulectomy.
Anyway, that's just my experience, and it may not be as severe with your dd. But I just would hate for someone else to go through even a tiny bit of what we had to endure when it could be so easily and quickly corrected.

Hope that helps somehow, and I hope that your problems don't get worse!
Also, the procedure was super simple. The ENT examined his tongue, then just put a bit of lidocaine-type gel on his tongue, waited a couple minutes, then took little scissors and clipped it. Took literally just a couple minutes, and ds really didn't fuss much. Maybe 3 drops of blood. They did warn me not to nurse him for at least an hour after, because the numbing gel might cause him to choke if I tried to nurse him before the numbness wore off. But he fell asleep in the elevator on the way back to the parking lot, and didn't wake up until 2 hours later! And as I said, he had no trouble, and seemed to have no pain from the clipping at that first feeding. It really was easy-peasy, and IMO, SOOOOO worth it!