Shopify and Facebook pixel problem

Old Facebook pixel and new pixel conflict. It was fine sync products from Shopify to Facebook, until I accidentally click on old store with same name of store, then Shopify products started sync to old store and the new Facebook pixel wasn't able to sync the products because they go the the old store . Need to remove old one and use new one. Its giving me instruction how to fix it, but I'm not confident how to do it.

Lucy P