If a person took 2 mgs lorazapam by mistake vs Advil (ibuprofen) for migraine what can be expected.

headache. Sedation, drowsiness, possibly dizziness, and all other effects and collateral effects of lorazepam. Try to avoid any future mistakes, only take what is prescribed for you. Migraine would still be there if Ibuprofen was the treatment and nobody took the tablet, unless symptoms spontaneously subsided. Ask your dr. Good luck.
Sleepiness. I would expect you will feel sleepy for4-8 hours. During that time don't drive or operate machinery. Best wishes.