Full Moon: At the beginning of your turn, roll a d6 once for all friendly characters with the Full Moon trait. On a result of [1] - [3], Werewolf can use Shape Change. On a result of [4] - [6], click Werewolf by Night to either click #9 or click #11 and click him to click #3 at the end of the turn or before he takes any damage, whichever comes first.

Curse of the Werewolf: When an opposing character takes damage from Werewolf By Night's attack, that character possesses Battle Fury as long as Werewolf By Night is on the map.

How long does Shape Change last if I roll it with Full Moon?
Until you roll Full Moon again and the result comes up [4] - [6].

So if roll a [4] - [6] on Full Moon, I will always go to click 3? Even if my Werewolf By Night was on click 6 and almost KO'd before?
Yes. You will always go to click 3 at the end of your turn or if the Werewolf By Night is damaged. And, yes, this means your damaged Werewolf By Night gets better... but also please note that nowhere does the word "healed" appear in this description. So game effects that would care about healing are not activated by Full Moon.