What I need to do is retrieve the JIRA issue created via the "Create issue" option in a pull request's comment

This seems to be related to Bitbucket / JIRA integration.
I saw an almost similar post but it wasn't quite the same: (it is retrieving the issues for which commits were made). It seems to use this API.
I would expect to need to pass the comment ID to an API and get it somehow but can't find the option. An option to create the issue is here with a POST. I expected a related GET.
Thank you. Hopefully you can point me to what I missed.