broken toe nail, with pic

Hello,

I have my sister in laws staffy for a couple of days. He has, which looks like a split toe nail. Im aware he did it last monday. He's not limping but i can see it is affecting him. He is constantly licking it. he is walking around and playing with my staffy but he stops to lick it every few minutes. I have wrapped it to avoid him licking it but then he will not move, and he took it off last night anyway.
Any recommendations. Is it a vet job? or will it heal on its own? Thank you

Keep it clean and it should regrow all by itself.  

You might want to wash it after walks with a mild salt solution. Is it the Dew claw ?.. If so, this is pretty common.