Does A Foot Injury With Hardness And Blackening Need Immediate Attention?

Hello, my daughter cut her foot right under her big toe this summer while at a friends house. I just found out that it still not healed. It now is hard and has a little bit of black under the cut. Do I need to take her to the emergency room tonight or can I make an appointment with my doctor this week? She is not complaining that it is hurting her but it doesn't look good.