This happened twice.. my Mage's LP is 1/1 and i have to go to the healer an pay a lot of money to regenerate it back
to normal. Is there another way to do it?

Yes. DON'T STARVE. The effect you are describing usually comes about from not eating nor drinking at all. Your characters will eat when you succeed at hunting while setting up camp in the wilderness (with improved rations) and of course if you buy a meal at the inn. But these actions are active (you have to do them). For passive stuff - your characters eat and drink automatically from their own inventory IF they have something to eat and drink there. They will inform you when they're out of food and water but will do so only once. However you had to ignore a large amount of warning pop-ups regarding starvation to get down to 1/1 LP.