vaginal cut from fingering

So last night I was getting intimate with my partner and he began to finger me. When he pulled his finger out he noticed blood and asked if I had gotten my period but I hadn't. So I looked down there and noticed a little scrape. I'm guessing from his fingernail. Has that ever happened to anyone? I was freaking out yesterday. Also, how long should I wait to have sex if I had this little incident happen last night