i told a lie about my homework

sooo i had this huge math worksheet last week and it was supposed to be like a study guide for the test on friday. but honestly, i did not do one single problem over the weekend. i got distracted by playing video games all day long with my bro. when we came back to school monday, mr. lewis handed out the homework checks and everyone had it done except me. so i told him that i worked on it for like an hour but had to go to my cousin's birthday party early afternoon and never got to finish. mr. lewis gave me a funny look but let me off with just a warning, saying he hoped next time i planned better. but the real reason was cause i was too lazy to do it over the weekend like we were supposed to. now its been gnawing at me all week and today in class when mr. lewis asked who needed extra help on anything for our test tomorrow, my hand kept shaking up by my desk cuz i wanted so bad to say 'me' but then i couldn't bring myself to do it. cuz honestly, i'm worried if i tell him the truth now that he will think im not responsible and make me do extra work or give me detention or something. but at the same time im like such a liar. maybe i should have just owned up to it on monday? but what's done is done and now i gotta study really hard tonight for my test anyway so i might as well get that part right.