I had to do this when I was eight years old because vets were not an option and I think it changed me for the better because it worked . I then became more confident . I hope I don't offend any one with my advise . Sometimes I don't explain good enough .
If you don't have stiches you can use a regular needle and thread I have had to do this in the past just make sure you alcohol the thread and needle pull the skin together and pretend you are sewing a pillow case shut one stitch at a time . Just put the needle through both skin sides and pull it...
I am surprised he is not in shock because I am . I love ducks . Shine a bright flash light into his eyes if his pupils are kind of jumping around that is shock setting in . It is very hard for me to explain . If it's only skin tear and you have some stitches maybe you could clean him and sew...