Restoration of SharePoint is always a mission critical task. You need to give full attention to the procedure that you will follow and you need rollback plan as well, if anything goes wrong.
I face this problem, when someone deleted (I presume) the user profiles and approx. 100 users already updated their profiles. So, I look for internet to find out the way to restore only user profile instead of whole _PROF database. But, unfortunately, I was unsuccessful.
So, I decided to test the whole action plan on virtual machine. Once, I satisfied the behavior of SharePoint that was expected, so I decided to restore the _PROF database from the backup that was taken last night.
The only way to recover user profiles with My Site is to restore the previous backup.
I restarted the SQL server services from SQL Server 2005 Management Studio in order to give exclusive access to restore activity. Once _PROF database is restored, I reset the IIS to clear the cache and here you go.