My sons mother is in the process of terminating her parental rights. She had custody then my son was placed in my care by Gregg county for good reason. My question is, what about back child support that I owe? Will I have to continue to pay that off or will it be voided since she wants no part of my sons life?

Only the court that issued the order of support can advise you of the status of your arrears. Ask them if the sitution can be changed. Who is adopting your child? Are you current in agreed upon payments?

Arrears are still owed unless a court releases them.

And what makes you think the mother can terminate her rights? Unless there is someone willing to adopt it is unlikely a court will grant a termination.