Contracted cancer? I helped a diabetic cancer patient use a lancing device and I stuck myself afterwards trying to remove the pin part of it. Cancer?

No. Just plain no. I'm sorry you were troubled by this. Cancer is simply not contagious. Now, if the patient has cancer secondary to having hepatitis or HIV, you will want to be tested -- in fact, if he/she is HIV-positive, ask your physician about post-exposure prophylaxis.
Not cancer but. you could have acquired any number of blood borne infections, namely, hepatitis, and HIV. Please see your doctor for baseline tests and may be prophylactic treatment. You do not need to worry about catching cancer this way.