You'll need to change the Prometheus ConfigMap to add new scrape jobs for the new targets. The Pods are in the kube-system namespace and they each have an app label.
Prometheus config isn't straightforward, but you can use this as a starting point, replacing the angled-brackets:
- job_name: '<x>'
kubernetes_sd_configs:
- role: pod
relabel_configs:
- source_labels:
- __meta_kubernetes_namespace
- __meta_kubernetes_pod_labelpresent_app
- __meta_kubernetes_pod_label_app
action: keep
regex: <ns>;true;<app>
Prometheus doesn't reload the config file when it changes, so you'll need to force a Pod update.
Need more? Here's the solution.