How can i reverse the side effects of long usage of cortisone ointment on face? scrub it?

Do not scrub it: See a plastic dermatologist or plastics specialist, and never use it again on or near face. See prior answers about this topic. A caution and comment about the fact that you mentioned an ointment. How potent a topical steroid is has an enormous amount to do with if it's in cream form (milder) or ointment form (much more potent); if use occlusive dressing over it, then ten times more potent.