Unlawful Possession Charge but I Have a Valid Prescription

My question involves criminal law for the state of: Colorado

I was arrested in July for having 2 Vicodin tablets in my pocket without my bottle. The charge was Unlawful Possession of a Controlled Substance (Class 6 Felony). I've had one court appointment where they just read the possible legal repercussions if I were to be convicted. I have a valid prescription and am bringing the information from my doctor to my second court appearance where I believe I'm being "formally charged".

Can I submit this evidence to the DA during my "formal charging"? Also what should I expect at a "formal charging" hearing? Should I file a motion to dismiss. I do not believe I need to spend money on an attorney since in fact it was not unlawful possession.

Any advice would be helpful.

The charge was filed under what exact statute? C.R.S. Sec. ____?