Hi @DashThisDev 
I’m an app developer myself and, as far as I’m aware, it’s not possible to periodically or programmatically refresh HubSpot public app client secrets. These are static values that are uniquely assigned at the time of public app creation. In saying that, a HubSpot rep may be able to help you by manually updating your app’s OAuth credentials, as per the accepted answer on this post.
Aside from that, I think the best we can do currently is to avoid exposing OAuth-related credentials directly within source code.
I hope that proves helpful.