Water Heaters - Help! Water heater leaking and have no water

I went to check the dip tube if it was disinegrated. There was still some water coming out above the nipple despite having the cold water valve and main water supply off; and I had the hot water turned on inside the house. It stopped once I drained some of the water out of the water heater.

I couldn't remove the nipple so I put back the cold water pipe onto the nipple and there is leaking once I turned on the cold water valve. I have not yet turned on the main water. I turned the cold water inlet as tight as I could, and it still leaks.

I could see water coming down the threads. Is there a temporary fix for tonight until I get a plumber tomorrow like thread tape or putty? I have no water other than what I saved.

shut the main...drain down the pressure from the bottom of the tank....and put the brass relief up to vent .remove the cold valve and teflon tape that nipple that is leaking down.4 wraps around then hand tighten the valve back on,and one full turn with a wrench on the part the nipple going into the cold valve.if you originally reinstalled it without white teflon tape that is why it is dripping now.