It's a focus, you can keep it and cast it every day. Though it should be straightened, cleaned, and cavity free.
Also
Keledrath's Unhallowed Pact
Evocation [Evil, Lawful]
Level: Sor/Wiz 3
Components: V, S, M, Special
Casting Time: 10 minutes.
Range: Personal.
Target: You.
Duration: 1 week.
You call upon diabolic powers, communicating your desire with a harvester devil or imp through this spell. When you complete it a contract for your soul appears in your hand, your copy, and you gain Fast Healing equal to 1/2 your caster level, an enhancement bonus to each physical ability score equal to 2 + 1/2 your caster level, an enhancement bonus to natural armor equal to 1/2 your caster level, and Spell Resistance 12 + your caster level for the duration.
Material: 1 ounce of blood.
Special: As part of casting this spell you sell your soul, and your copy of the contract appears in your hand. You may not cast this spell if you do not have a soul to sell, or have already sold your soul.