It appears to be the BR side so if it doesn't have to match other doors thin (¼") plywood strips wide enough to cover damage could be glued and brad nailed to the door face simulating stiles and rails. If the door is to be painted cheaper hardboard strips could be used.
My son considered doing something similar on three doors opening into a hallway but is still procrastinating. I think he was going to simulate panels as well. Another option is to look for a second hand door. Sometimes they can be found at craigslist.com or facebook marketplace when people are upgrading to solid doors.