If you really want a patch that matches the existing exactly, look inside all the cabinets and storage spots. You may find a piece that you can peel right off (they use tiny staples that barely hold). Then find any old piece of 1/8" plywood to put back in it's place.
Whatever you do for a patch will show. Making it look like an access panel is a good idea. There is plastic edging trim for luan in RVs which would dress it up. I'd cut the damaged area out in a square/rectangle then slip in a piece of 1/8 - 1/4" plywood as a backer and use small #5 - #6 screws to hold the patch in place. Or could glue it.
Depending on the height of the damage, another idea would be to use the horizontal band/strip that they often (always?) stick on walls in living areas. It's thin plastic with a self adhesive backing and would be in a roll. Patch the damage first.
Or attach something over the damage like some diamond plate aluminum or whatever. Maybe make a padded headboard?