I would advise keeping a close eye on her and if the behaviour continues you may want to take her to the vet to get checked out.
However, dogs are fairly resilient. I have noticed my dog limping before and it passes almost as soon as it began. If she was bitten by something, it may cause her some pain and discomfort for a short while, but will probably heal itself without the need for treatment or an expensive trip to the vets.
If it continues to cause her problems she will most likely let you know! Dogs do not tend to suffer in silence. So if she continues to limp, yelp or growl, or is off her food, this could indicate that it is something more serious.
In terms of home remedies, a weak solution of water and baking soda applied directly to the wound may ease the irritation if it is indeed a bee sting.