04 Alero 2.2 litre oil filter leak

I've owned this car about 4 years and always change oil and filter myself. The filter housing is cast into the block and has an o-ringed plastic cover that requires a 1 1/4" wrench to remove and replace. I've had no problems until recently. Can't get the cover to stop leaking past the o-ring. Not a large leak just enough to create a mess. Any ideas?