I'm not exactly sure what you can do yourself. Usually a guitar with a non adjustable neck would need to be secured and tension applied to the neck for an extended period of time.
Did you also check inside of the sound hole to make sure that there is no adjustment at that end of the neck? Other than that perhaps try shaving down the saddle to lower the action a little.
Did you also check inside of the sound hole to make sure that there is no adjustment at that end of the neck? Other than that perhaps try shaving down the saddle to lower the action a little.
