How long was the collection being shown on your account? The longer the more your credit score will drop.
What you can do to get the cerdit score back up is; use a credit card (with no balance) for small purchases each month such as gas, or a meal here and there then pay the balance at the end of the month. This is called revolving credit and in the long run bulk up your FICA Score. It shows creditors you can use a card frequently and not acrue a large balance like most idiots do.
Keep in mind if you have a balance on your credit card don't do it.