He did something in addition to enabling USB debugging. (I can't remember the last time I ran a phone with it disabled, except for immediately after reflashing a ROM, before turning it back on.) It has no effect on battery drain, and doesn't add any files.
I'd suggest that you ask him, insistently if necessary, to undo what he did to your phone. If he won't, see if your carrier can reflash it - that will get it back into the state it was when it came out of the box. (Back up any pictures, music, etc., because the newly-flashed ROM won't have any of your files in it, so anything you don't back up will be gone forever.) Then don't let your boyfriend play with your phone.
10-19-2018 01:12 PM