Unwind the end of a paperclip to use as a grabbing and pulling tool.
Identify the small loop next to the pulled loop. Because the adjacent loops on a Berber carpet are connected, if you pull one another loop will be tightened.
Slip the end of the paperclip under the smaller loop and pull it gently. Do not tug or pull hard, as you risk snapping the thread. Pull until the smaller loop is the same size as the pulled loop.
Remove the paperclip.
Place a dab of non-water based glue on the end of a toothpick.
Dab the glue onto one of the bases of the pulled carpet loop where it goes through the carpet backing.
Bunch up that end of the loop so the loop is the same size as those around it.
Hold the loop in place with your fingers until the glue sets, according to the manufacturer's instructions. This could take several minutes.