help! what's wrong with my dog?

[permaquandry]

Mini schnauzer (1yr old) had a long walk and a boisterous play with a huge greyhound yesterday. Ever since has been licking back left paw and limping. Washed the paw out and had a good look, can't see anything in there, other than red skin where she's been licking.

It's worse this morning. Does this sound like muscle strain?

I guess it's a trip to vets if no better tomorrow, any advice of what I can do in the meantime?

Thanks.