Oh no, My first chick injury ( I think)

[Nslangton]

Went out to play with the chicks. I noticed a black ring around one of the Leghorns toes. At first I thought maybe something like one of my hairs was wrapped around it. I washed it off and got a better look. It doesn't go all the way around the toe just about three quarters. It is a little swollen around the toe. I think it might have got cut and started to heal already. Is there something I can put on it? Or is it an indication of something else going on with her? Thanks for any replies.