IF he is one of the less than 1% on the population (1 in 100 people) who has hep c, and IF he cut himself enough to bleed, and IF you forced his blood into your blood stream you risk would be somewhat similar to the situation where a healthcare worker should experience an accidental needle stick involving a person with KNOWN hep c their risk is only about 1.8% of transmission
Your risk is based on several what if scenarios and 1% of 1.8% or about 0.018% assuming all the other what if situations should align.
In theory you have a risk less than 0.018% or in others words an EXTREMELY low risk.
Or put another way your odds of getting struck by lightning in your lifetime is about 0.083% vs your odds of getting hep c in this situation of 0.018% so you are at 8 times greater risk of being struck by lightning.