Answer:

Hi,

As you cannot access to the SP logs, in order to troubleshoot the workflow, please try to insert a “log to history list” action in your SPD workflow  that write to the history list to allow you to see the status of the workflow, The Workflow History List which was a hidden list and located in http://yoursite/lists/workflow history/. For more information about troubleshooting workflow, please refer to: http://technet.microsoft.com/en-us/library/cc298927.aspx

Or you can recreate the workflow and then check if the changes are being shown on the SharePoint site, I think that the workflow may be corrupt.

Let me know the result.