I believe they molt 1-2 times a year. However there are things that can trigger a molt, such as extreme diet change and extreme change in how much sunlight he can get. If you can feed him LOTS of fresh veggies and fruits and sprouts, and get him in sunshine (with the option to go in the shade and be sure he is safe and has cool water) for as much of the day as possible, he may go into a molt very soon. It would also be wonderful if you could give him a good soaking bath once a day and let him dry in the sun.
Of course as I say this i realize it is winter for a lot of people and very cold. Obviously dont take him out in the cold. Windows filter out the rays that birds need, so putting him near a window won't do much good and could just let drafts get to him. You may consider full spectrum lights designed specifically for birds, but there is controversy over how much good those do, and how safe they are.
What part of the world are you in?
I wouldnt say you should be "overly" worried, but realize that a trim that severe likely has caused him some major insecurity. Be patient with him if he seems to bite first and ask questions later. Also, he may already have injuries because of this clip. Are you able to take him to an avian vet? He may also keep the habit of plucking after his feathers grow out. It's hard to tell right now. Be sure to keep his mind busy with lots of toys, interaction, new experiences, and things to shred. That should help if he is plucking out of boredom.