There is a very little tiny bit of truth in that statement as Lyme Pickle said - but the symptoms will continue to diminish as the body continues to heal. My nerve pain was only just getting to where I wasn't noticing it all the time (3 years past stopping Lyme & Bart herbs), when I got hit with it again.
I had kind of forgotten how bad it hurts!!!
Now, with that being said, I have noticed a few things that didn't improve with being 3 years past treatment - numb spots on my skin, lack of reflexes in my lower legs, memory still wasn't where it should be and a few other things. Although I do have to say that it was close enough that most people had no clue that I had been affected like I was.
What the docs that use that term are referring to though is that you supposedly live with that same amount of pain and other issues the rest of your life - which is not the case if you are treated properly the first time around.