If your partner takes any kind of damage and losses all their heath it's pretty bad and means you'll have to start over on things like battles. They take most of their damage from when your guiding them to items and other things though. Theres an easy trick to healing them that may go unnoticed. If your partner is on their final bit of heath make them come back to you as quickly as possible. Once their near you just place them on your back then let them off again. This will heal your partner and save you the trouble of redoing things.
If your like me you've accidentally bumped into a Demon Scroll once or twice. Now if you don't want to fight or are to weak at the moment to fight then theres a way to escape. On the wall that surrounds you you should see a yellow crack in the wall. All you need to do is attack this weak point in the wall. Doing this will cause a small opening to show up there. Now to get away from the demons just go through the opening and your home free. Attacking the cracks with your weapon works the best though you can also use the slash attack to make a opening.
Complete the Story and save the game when prompted. Then select 'Continue' at the 'Title' screen to start a new game with ALL health and ink pots previously earned in your original playthrough. Bonus items that you previously unlocked will also be retained.