Today, 11:24 AM
Often moms will experience something we call "the 10 second sizzle" when the baby first latches on. It's something of a misnomer because the pain can last longer than 10 seconds. The important thing is that the pain subsides after the baby has been nursing for a while. What is usually happening in a sizzle situation is that the baby's initial latch is shallow, and the nipple is landing too far forward on the tongue, and is getting compressed between hard palate and tongue, which causes pain. After the baby has been nursing for a while, the nipple is pulled into the ideal position on the back of the tongue under the soft palate, at which point the pain ceases. As long as the shallow latch is not causing nipple damage, this is not an urgent problem, and mom can work on it with the expectation that the baby will grow out of it. As the baby gets bigger, and her mouth gets bigger, she will be able to achieve a deeper latch right from the start.
Now, compression from a shallow latch would explain the crease you're seeing when baby comes off the breast. But it sounds like you currently have a lot of milk, so it's possible that in addition to having a shallow initial latch, baby is also purposefully shallowing her latch at different points during the feeding in order to control rapid milk flow.
I personally think that you can operate under the assumption that things will improve even if you do nothing. However, I would also like to have you go back and see a...