I'm cited for Misdemeanor - PB4140 Unauthorized Possession of Hypodermic syringes. CA AB 1743 allows persons to posses syringes. What can I do?

I'm a student at Cal State Fullerton and at the time of this incident I was living on campus, temporary. I'm no longer living on campus. Police were called because they got a call from someone saying that my "friends are smoking meth" I had no idea that these "friends" were doing illegal activity for I was in my room. They were charged with Possession of illegal substance. I informed the officer I was on Probation, resulting in search of my room and found hypodermic needles in a gym bag from an old gym buddy who left them in a bag. I didn't know they were in there. I had an old prescription bottle with my name on it in the bag so they assumed the needles were mine. Effective January 1, 2015, section 4145.5 of the Business and Professions Code states,” a person who has reached the age of 18 may obtain an unlimited number of syringes from a physician or pharmacist for personal use. No prescription is required, Any suggestions or advice?