So this might be a few years late to give any useful information to you guys, but! It seemed to me as though the reason for acrylic working to stop the nail growing into the bed was unclear.
I'll try and explain as best as I can.
Your nail is growing into the sides of your nail, you have a thick nicely applied professionally performed coat of acrylic on that nail.
Now think, a thick coat of acrylic isn't going to be able to grow into the sides of your nail right? The acrylic stops at the sides of your skin as your nail is trying to grow into it. How can it possibly grow into the sides of your nail and follow your natural nail into your skin, that's the point it is like a barrier, but acrylic can grow forward because there is nothing stopping it so it will. Your nail isn't just going to stop growing so it's gotta grow somewhere and it can't grow into the sides.
Believe it or not there's something I don't understand though, if your nails have already started to grow into your skin and aren't visible at the free edge, as they grow forward will it not push through your skin to grow forward even if slightly in grown? Ouch.