Will my credit score go back up after I pay my school loan?

Hi there! I am three months late for my school loan payments and it knocked down my score. I'm going to pay the total past due now and keep paying my monthly fee. Will my score go back up a little a while after I pay the past due or is it going to stay the same? Also, am I able to call Great Lakes and get my payments a little lower a month after I pay the past due? Thanks so much! :)