From the U.S. CDC:
Needle stick Risk for Occupational Transmission of HCV
HCV is not transmitted efficiently through occupational exposures to blood. The average incidence of anti-HCV seroconversion after accidental percutaneous exposure from an HCV-positive source is 1.8% (range: 0%--7%) (73--76), with one study indicating that transmission occurred only from hollow-bore needles compared with other sharps (75).
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5011a1.htm
If you know for sure that they have hep c, don't take any chances. Dirty needles are the #1 way this virus is transmitted. The amount needed is smaller than a dot on this page.
Get tested!
Yes thats how I caught it.One time stick with a needle.
Any needle stick should be a cause for concern. There can be no assurance that there was no blood in the needle, because capillaries are very small, and they run everywhere in our bodies. Even tiny amount of infected blood can lead to Hepatitis C infection. This virus is very contagious.
If you ask for yourself, you need to get tested for hepatitis C antibodies, and for PCR if antibody test is positive. I really hope that you test negative, but you need to get the test for your own peace of mind. It is better than to play the guessing game.