I am sorry to hear about this concern.
I get a bit nervous with a acute onset of limping, because I cannot rule-out a more serious injury like a fracture.
Ideally, an examination should be performed. If there is any swelling that develops or distinct pain in any part of the leg, that an examination is critical including getting some x-rays done.
Aspirin. Not a huge fan but it can be given to dogs.
The only over-the-counter non-steroidal anti-inflammatory I recommend in dogs (NOT CATS) is aspirin. Due to potential toxicity issues if not dosed correctly, many veterinarians do not consider Tylenol, Ibuprofen (Advil), and Aleve safe.
You can give 10mg per pound of body weight up to every 12 hours. Just remember, there are different pill sizes for aspirin, so look to see if it is regular strength or maximum strength.
Aspirin can be upsetting to the stomach, so discontinue if any digestive upset and definitely consult a vet if not helpful. If available, buffered aspirin, with the enteric coating, can help as well. Sometimes giving some Pepcid A.C. antacid 1 hour beforehand can be helpful.
Pepcid A.C. (famotidine) comes in 10mg, 20mg, or 40mg tablets.
You can give it every 12 hours. You can give 0.5mg per pound of body weight. So, a 20 pound dog would get 10mg.
***Do not give aspirin or any other non-steroidal anti-inflammatory medication if your pet is already on prednisone or any other anti-inflammatory medication***
Severe stomach and intestinal ulcers can result from giving a pet aspirin, tylenol or ibuprofen when they are also on medications like Rimadyl, Deramaxx, Prednisone, Metecam, Zubrin, and Previcox***
So, at 70 pounds, you could roughly give 2 tablets of aspirin with a full meal.
Sorry to hear about the injury. Hope that information is satisfactory.