Kinda concerned

so me and my ex just had phone sex and you know I was masturbating and when we finished I looked down and saw blood on my hand but not dark blood and it wasn't that much but it was quite a bit and I'm not sure if I'm bleeding still. I thought maybe it's my period but eve says it's supposed to start in four days so maybe I injured myself? I have fake nails and they're I guess sort of long but I didn't feel anything while you know it was happening so what is it? should I be concerned?