Obsess or obsess means to occupy someone's thoughts or feelings; to haunt --
This is a new medication; if morbid thoughts obsess you, call the doctor.
He doesn't want to forget; he wants her memory to obsess him always.
Obsess may also mean to be preoccupied; to have one's thoughts haunted --
Don't obsess over it; maybe you'll win next time.
She tends to obsess over perceived snubs, but she'll get over it.
Abscess or abscess means a swelling or inflammation of a part of the body, caused by infection --
He has an abscess; will you make a dentist's appointment for him?
He has an abscess on his foot, so he'll need a wheelchair.
Now that you know that, you can say --
"She has an abscess in her jaw, and the pain medication is causing her to obsess over some strange ideas."
