Suffer the Flesh
You can draw upon your physical endurance to increase the power of your spells. You voluntarily deal Constitution damage to yourself when you cast this spell. For each 2 points of damage dealt, your caster level increases by 1. You cannot take more Constitution damage than your caster level (maximum 10 points for a +5 caster level increase).
Your maximum and current hit points drop appropriately for your lower Constitution score. A creature that has no Constitution score, or that has immunity to Constitution damage, cannot cast this spell.