It may just be leaking from the back of the valve cover gasket at the inner corners ( by the cam bearing)
Try retorquing the valve covr gasket (did I mention the torque wrench?)
make sure to use a criss-cross pattern .

( did I mention the torque wrench?) not to be repititious, but I fought mine leaking until I broke down and used the in lb torque wrench on it, bringing it down in boringly fine incriments before it would seal . I have the thick German rubber gasket and that thing is picky.

Getting it tight may take care of the leak at the back unles it is comming from the seal.
spray some simple green back there , let it sit a few minuits and hose it off good, then keep an eye on it for a few days to see if it's actually comming from the seal , or the gasket.

if still the gasket, try taking it off, cleaning it up good and putting it back on with some sealer in the inner corners.

If the cam seal, you'll have to loosen the pump, remove the back cam gear to replace the seal( special tools needed retime, etc., if you just did the head, I imagine you have them)