After My Day At School Today I Noticed That My

After my day at school today I noticed that my big toe on my right foot hurting. When I got home I took off my socks and noticed a black spot just around the tip of my toe nail. I wear black socks so I'm not sure if it's just because of that but it seems to ne under the skin, not the nail. I just want to know if it might be infected or if it would just go away after some time. Thanks for reading!