How long will my dq papers stay in the army database?

i was dqed from the army after meps for admitting to have used a controlled substance... that was over a year ago, and i was 18-19 yo when i was screwing up my life, im 23 now and have been on the right track. my recruiter told me it wasn't a big deal at the time, then before my papers ever came back she was out the army and i was dqed... my question is if i try again say for the marines and just never say anything will they find out?i applied twice and was denied both time, then i wrote letters to the dod and to the senator of florida and all came back negative. all i want to do is serve all my friends and my brother is over seas. please any help.