I'm 16, i have lesions on my brain, have constant migraines, been takin a lot of tylenol (acetaminophen) in the past 2 days and i've been throwing up, what should i do?

Safest thing: Is to go to the er. Unsure of brain lesions, but increased intracranial pressure can lead to nausea. If you have taken too many tylenol, (acetaminophen) this could also lead to acute liver issues/failure and you would still need to go the er. I would recommend going to er either way and getting checked out as soon as possible. Best of luck and my thoughts are with you!