Is there any way to track/trace/find an IP that a user account has logged in as? I feel like I have a user logging into the wrong account and is doing some damage...
Check your IIS logs for the SharePoint site. By default, IIS logs that information, so if the web server knows the data, it will be in there.
This will hardly be a SharePoint feature. I am no expert on Windows Server but it could be done by using the audit logs from your domain controller. Configured correctly it should log all logins and MAYBE the IP that belongs to it.
You should be able to find better help on an Windows Server forum.
What you could do additionally is turn on audit logging for SharePoint to check what that user does.