Salut mec, je vais t'écrire en anglais comme c'est la langue ici mais tu devrais comprendre sans trop de problème.
As I went through a lot of puff painting with my suit (over 6 month to cover the whole dman thing with 2 layers, yes 2 layers), I think I can give you some advice.
First, it's always easier to puf paint your suit while it's flat and have some tension.
But as your suit is already sewed, I would recommend you to make a dummy of your face using some duct tape (tu peux trouver ce genre de scotch pour pas trop chère à Leroy Merlin)
Here's how you can make it, but you'll need someone to help you.
First, cover your hair with a bathing cap to protect your hair. Then, wrap your whole head using saran wrap (cellophane).
Make sure to do some holes in front of your nose to breath. Two little holes are more than enough, juste relax and breath slowly.
http://image.noelshack.com/fichiers/2014/12/1395535663-capture-d-ecran-2014-03-23-a-01-41-00.png
Then, repeat the same step using some duct tape.
In the end, it should look like this. Warning, the person helping you might take advantage of the situation. Try to stay calm, breath slowly and try not to laugh too much
http://image.noelshack.com/fichiers/2014/12/1395535661-capture-d-ecran-2014-03-23-a-01-41-05.png
Then, carefully cut the duct tape shell and close it back with more tape.
Fill it with some coton inside and you'll have a head a tiny bit smaller than your own head, but it will definitely help you with the puff painting part.
Another advice. Try to really take your time when puff painting your suit. I know it's exciting to see to see it the more and more advanced, but taking your time will definitely give you much cleaner result and a more machine like look.
Also, use some application tip like this, it will help you have a thinner line but as you already started, I would advice you to keep going the way you did, just for consistency (tu en trouvera à Cultura).
http://www.imaxshop.com/media/catal...eda06f020e43594a9c230972d/h/e/hennabottle.jpg
Here's what mine looked after a LOT of hours going through the same process as you.
http://image.noelshack.com/fichiers/2014/09/1393359289-capture-d-ecran-2014-02-25-a-21-14-12.png
http://image.noelshack.com/fichiers/2014/12/1395536491-capture-d-ecran-2014-03-23-a-02-00-40.png
http://image.noelshack.com/fichiers/2014/12/1395536491-capture-d-ecran-2014-03-23-a-02-00-26.png
Bonne chance et bon courage