We have two chinese firebelly newts, the other has turned terrestrial in his/her old age, but the other is still in the water and as the original poster's newt grows papillae on an off at all possible times of the year. Sometimes a few weeks go without him having them, sometimes it's only a few days until they appear again.
I thank you who have replied to this thread. We've been concerned at times about the papillae, thinking whether or not it's a sign of everything not being ok with him. I thank you for putting my mind at rest. Tau, the papillae carrying newt, however is not very restful since growing the papillae makes him march rather frantically around in search for pretty girls who sadly are nowhere to be had.