You will learn at OCS that integrity is more important than anything else. Integrity is the adherence to moral and ethical principles, soundness of moral character, and honesty. The fact is you screwed up and you need to take responsibility for your actions.
There is no doubt that hiding your mistakes is the easier route. But if you choose to hide something in your past, and it comes up after you have become a Marine Officer, there will be hell to pay.
Be honest with your OSO and he/she will tell you what needs to happen for you to become a Marine.