Unless otherwise noted, damage to your ability scores is healed at the rate of 1 per day to each ability score that has been damaged. Ability damage can be healed through the use of spells, such as lesser restoration.
So if you/your party don't have access to the lesser restoration spell (or higher-level spells), or a potion of that spell, then you'll simply have to wait until the damage heals naturally.
Don't forget:
PRD
"Long-Term Care: Providing long-term care means treating a wounded person for a day or more. If your Heal check is successful, the patient recovers hit points or ability score points lost to ability damage at twice the normal rate: 2 hit points per level for a full 8 hours of rest in a day, or 4 hit points per level for each full day of complete rest; 2 ability score points for a full 8 hours of rest in a day, or 4 ability score points for each full day of complete rest."
So with complete rest for 24 hours and someone to make a DC 15 heal check on you, you can recover 4 points per day.