What leg is the dog limping on?
Is it only after rest?
Does the dog bear weight on the foot or hold it up all the time?
Thank you for that information. This can be due to a few things. This breed is prone to hip dysplasia which would show pain when trying to rise and would also show lameness. http://www.petplace.com/dogs/hip-dysplasia-in-dogs/page1.aspx
Smaller breeds are also prone to disc problems along the spine. This can cause lameness in one or more limbs and in severe cases the dog may yelp when touched or moved. http://www.petplace.com/dogs/intervertebral-disc-disease-thoracolumbar-area-in-dogs/page1.aspx
Another reason for not bearing weight on the foot is a torn ligament in the knee. This can lead to intermittent limping to total non weight bearing lameness. For dogs under thirty pounds usually rest and anti inflammatory meds are given. If that does not work or if the dog is over thirty pounds then surgery is necessary. This is more seen in larger breeds but it can happen to any dog.
If you are planning to bring her to a vet tomorrow then don't give anything for pain unless it is something like rimadyl that she has had before. If you cannot get into the vet for a few days then you can give aspirin, however this can not be used for more than 2-3 days or stomach ulcers can occur, nor can it be used if the dog has a history of clotting disorders or kidney problems. Make sure to use buffered aspirin and not Tylenol, Ibuprofen or anything with acetaminophen as these are toxic to dogs. Make sure to tell your vet if you have used aspirin as any other pain medication he may want to give may have to be withheld until the aspirin is out of the system. Give aspirin with food. Here is more info and a dosing chart. http://www.petplace.com/drug-library/acetylsalicylic-acid-aspirin/page1.aspx
You can give plain human aspirin. Give with food to help coat the stomach. Baby aspirin will also do . Generally dosing is one baby aspirin for every 16 pounds of body weight. Have a happy holiday!