Low oil pressure issue

[jesserctc at charter.net]

HAs anyone here experiences low oil pressure to a damaged oil filter?  I was too busy with school so the wife took the car to the Valvoline for an oil change.  After about a month the oil pressure was way low.  Light would flicker at low RPM and at anything above 2500 RPM the lifters were clacking like crazy.  When i started checking for a cause i noticed that the oil filter from Valvoline had a big honking dent in it, either before it was installed or during installation.  Otherwise i cant find a good reason for the pressure drop.
Any input would be appreciated.

Jesse