Disability or FMLA question.

I know, wrong category but everytime I post on other threads, I get no response.

Ive been at my job for over three years. i have never taken a leave of absence.

I am having to schedule dental surgery soon and I want to take off work for 1 to 2 weeks to recover. I have no PTO accrued because I use my PTO as I accrue it, instead of taking all at once.

My question is.. Do I go ahead and take off work for dental surgery and THEN apply for a PAID leave of absence due to medical issue? Or do I apply, then have to wait for approval before I schedule my surgery?