What are the chances of contracting hep C from sharing a razor?

I'm a 13 year old male, 100 pounds, and 5'7. I don't know if that's necessary or not, but I want this to be reliable. So yesterday I was hanging out with a friend, and I wanted to shave since I had a date coming up. I asked my friend who had been tested recently, if I could use his razor. He said yes. So I went into the bathroom, and grabbed a razor out of a bin of his stuff. When I was almost finished, his step dad walked in and said the razor was his. I had a panic attack (I have panic disorder and OCD) because I though I could have just contracted an STD. I'm vaccinated from hepatitis A and B, but C is what's really worrying me. Especially because I know it can lay dormant for decades without the person knowing. Next time I see him, I'll definitely ask him if he's been tested recently. But are there any other precautions I should take? What are the chances of contracting hepatitis C from one shave? I'm really freaking out. If someone could reply soon it would be greatly appreciated.