After taking damage, you can recover hit points through natural healing or through magical healing. In any case, you can’t regain hit points past your full normal hit point total.

Natural Healing: With a full night’s rest (8 hours of sleep or more), you recover 1 hit point per character level. Any significant interruption during your rest prevents you from healing that night.

If you undergo complete bed rest for an entire day and night, you recover twice your character level in hit points.

Magical Healing: Various abilities and spells can restore hit points.

Healing Limits: You can never recover more hit points than you lost. Magical healing won’t raise your current hit points higher than your full normal hit point total.

Healing Ability Damage: Temporary ability damage returns at the rate of 1 point per night of rest (8 hours) for each affected ability score. Complete bed rest restores 2 points per day (24 hours) for each affected ability score.

Increases in Constitution Score and Current Hit Points: An increase in a character’s Constitution score, even a temporary one, can give her more hit points (an effective hit point increase), but these are not temporary hit points. They can be restored, and they are not lost first as temporary hit points are.