You don't just wet the drum head. It should be checked thoroughly for proper seating. Then, you can brush a damp rag over it to allow it to form. Do not get the hoop area wet. Tension it just a bit. Allow it to cure for a day. Check the sound. Tension it just a tiny bit more and check for sound. It should be humming by now. Let it sit for another day. When you come back to play, it should have seated and formed to the drum. You will need to check the drum sound each and every time you play. Do not tighten a calf head anywhere near a plastic head level of tension. Don't wail on it.