I'm not too familiar with mouth swab tests but I'm pretty sure that it wont test for lortab unless it is an extended drug test and or specifically testing for lortab. Even though lortab is an opiate, it doesnt break down into morphine like heroin or opium so you will not test positive for it unless like I said there is a reason to specifically test for it. Painkillers normally stay in an average persons urine for 2-5 days depending on how frequently used. Drugs stay in your system much shorter in saliva so mouth swab testing will most likely only be positive if you used in the past 48 hours. Good luck too you and I hope this helps