I'm worried about acne scars. How long will the procedure take?

I am considering laser treatment because the acne scars from puberty haven't gone away even after becoming an adult. I've heard that it's difficult to see results with just one or two sessions; typically, how many sessions are needed to see noticeable improvement?

 

As a working professional, I am concerned about long downtimes, so I would like to know if there are any procedures that allow me to resume my daily life immediately. Please share any procedures or packages you would recommend!