Is it really that hard to write an essay on cigarettes? If it's this or face possible jail time, then just suck it up and accept your parents' punishment. While I wouldn't generally condone parents getting law enforcement involved if drugs is the only issue, the price you pay for being dependent on your parents is that you have to learn to abide by their rules, not get caught, or sometimes accept punishment when you do get caught.
I don't know anything about your life situation and I don't know what your relationship with your parents is like but if it is only your drug use that is causing the problem then try to understand that their efforts to control your life probably come from a place of love and concern rather than actual malice and an aimless desire to control you for no reason. This is a cliche but it's something you'll realise when you get older. Of course, I don't know how old you actually are but judging from your post you sound young.
You don't have to give up drug use, I used drugs while I lived with my parents and it did sometimes cause friction but I managed to keep things under control by firstly, mainly using drugs outside with friends, and not in my parents' house, and secondly, being meticulous about hiding evidence and my own use whenever I did use drugs in the house. Leaving empty DXM bottles around is just an amateur mistake, but of course it's progressively harder to be careful if you're getting fucked up all the time, and if you feel like you need to be high all the time then this is an issue that you should address as well, while you still can. Especially if it's got to the point that you can't just take a break from using for the sake of being able to continue leeching off your parents (not meaning this as an insult - I did this too for a while and I recognise it now, but it's a luxury that many people don't have and you shouldn't take for granted).
Obviously there could be other factors which make leaving your parents' care a more reasonable decision, but since you've only mentioned the drugs I feel like I need to present an alternative viewpoint to you here.
I know you want to keep doing whatever you want to do with no consequences but hey, welcome to life.