Contrary to popular perceptions, HCV is not generally sexually transmitted -- and your question doesn't concern sexual transmission. So this question is somewhat off topic for the STD forum.
In theory, shared razors can increase the risk of transmission of any blood-borne infection, like hepatitis B and C and HIV, and standard prevention advice is that people should avoid sharing razors with persons they know to be infected. However, shared razors, toothbrushes, etc, and other methods of potential exposure to blood or body secretions, occur all the time in households -- and yet household contacts never catch those infections, assuming they aren't having sex (for HIV and hep B) or sharing injection equipment (for HCV) with the infected person.
Having sex with women while they are menstruating does not significant increase the risk of sexual transmission of any of these infections; that comment about your friend is irrelevant. That he is a health care worker increases his chance of having one or more of these infections, but almost certainly he would know if he had one of them. (By the way, there are no "regulations" (i.e., laws) about testing health workers after possible blood exposures -- just recommendations by experts and individual institutions' policies.)
Finally, even if your friend is infected, the chance of transmission from any sharp instrument 36 hours later, even if there was visible blood on the razor, is zero.
Bottom line: No risk, no need for testing. Don't worry about it.
Since this is off topic for the forum, let's not have an ongoing discussion. There are other sources for discussion of hepatitis and transmission of other blood-borne viruses.
Regards-- HHH, MD
Thank you for your response to my miscategorized question. I apologize - I definitely had such misperceptions after over reading.
It's not a problem -- don't feel bad. We take lots of questions about nonsexual HIV transmisison. It's just not the main focus of this and the HIV prevention forum.