Until or unless you know exactly what's wrong she should be restricted to leash walks only until the limping is completely gone.
If there is no evidence of a puncture wound or cut she might have a tendon or joint issue. Tendons can take a long time to heal and if pushed more tendon damage / scarring can occur.
Just like with people.
The last time I helped a limping lab it was my buddies. After a long day of pheasant hunting, she started limping real bad. He thought she was just sore, but at 3 yrs old it seemed a bit odd. I started checking her leg and foot out and found a huge thorn, about 3 inches long, had penetrated one of her pads. It was completely through her foot, and you could see where it was poking out on the top of her foot. Holy smokes it looked painful! We got it out in one piece, and she handled it like a champ! Filled up a bowl with cool water and she stood there for about 20 minutes with her paw in it. Pretty funny to watch.
I wish I could remeber what the tree is called with the giant thorns on it that got her. I call them death trees, but I think they may be some kind of apple tree??????
Those things are nasty. I've got a ton of them on my property and they aren't fun to walk into before daylight during turkey season.
I watched a buddy pull one out of a cats nose once too. It was his mom's cat. She noticed something stuck in its nose and it was bleeding. I held the cat with gloves on and he used pliers to pull a 2" locust thorn straight out of its nasal passage. I figured that it would have done more damage than it did. It poured blood for a little while, then situation normal. As far as I know it's still alive and well.