Don't use plumbers tape unless ya know what your doing to easy to cross thread such a fine thread or lock it on which generally involves breaking something getting it back off., first find the leak..Use some dishwashing liquid in a spray bottle and spray the nozzle area then add some air and see where its bubbling. More often than not if its the head assembly a slight tweak tighter will stop the leak as if it has a teflon or rubber seal its likely your just no longer getting compression on the seal by handtightening, some peeps dont like tightening nozzles but has never caused me any harm. Bees wax or a chap stick if that doesn't stop it or even replace the seal if its a sealed unit. If its a metal to metal seal like with the nozzle sitting on a machined face, try recleaning the mating faces also.Good luck