The same thing happened to my left hand pointer finger. It got caught when closing a School door!
Leave it alone & it will eventually grow back, try NOT to damage the cuticle area & leave that alone too. It will grow out depending on how long your nails take to grow. Some people have nails that grow out quickly, but I noticed my damage finger nail grew out way slower. I lost the nail twice in 1 year due to acrylics. NEVER EVER let them (manicurist or do it yourself) soak off the acrylic as that does weaken the nail bed & knocking it by accident causes further damage to the nail bed. I know it's hard, but try to be patient with it. As I stated I lost mine twice in a year (due to soaking off acrylic & it's the only nail where I have a fake nail put on due to the damage), so I had no nail on it for over a year.