
Years ago we had littermates, brother & sister. while out walking the male tripped while running at full speed, injuring his leg, he was in such a state I had to carry him 1 MILE home (he weighed 4 stone

). Got him to the vets and it was a sprain. The next day, his sister developed a limp in the vey same foot, even though we were sure she had not injured it she was taken to the vets. The ve found nothing wrong with her atall. All we could deduce was that she saw the extra attention the male was getting and was smart enough to put on the limp in order to get the same TLC. Funnnily enough, the very same day the males limp had gone, hers had gone too!!!
So, to sum up my waffle, if your dog had recieved a fuss/you were acting different towards him because of the bad leg, he may well have felt like making it into somthing more than it was. Our dogs are very sensitive to changes in our moods/behaviour which in turn effects thier behaviour and they can manipulate us much more eailiy than we give them credit for!!
My last dog was prone to ear infections, if I fussed over him when he had one, he would act like he was dying & needed constant cuddles, if I treated him like normal, he acted like normal! Funny things!
Personally, if it doesn't bother him much & he seems himself (no temperature, no signs of distress/lack of apetite etc.) I would just keep an eye on him, but if no improvement in a few days time I would take him to the vets anyway, just to be on the safe side (obviously if it gets worse again it's best to take him to the vets).
A good tip for things like this is to take a home-video, as many dogs make a 'recovery' while at the vets, but if you have some video footage to show the vets it can help. I did this when Buster was diagnosed with ED, his limp would go at the vets (prbably due to feeling the need not to show weakness/injury) so I had to film how bad he was at home for the vet to see it.