@shenzimaria I am sure you have your reason for the fight right there -
"a boy who was at home was teasing them we think that they were nervous because of that. Apparently everything was very fast, so we don’t know very well what’s happened"
And I agree with DonC, it is wrong to apportion blame to either dog if you didn't actually see the fracas start. I am sorry this happened and you may have to work hard to get them to trust each other again.
Best is to keep the two dogs crated within sight and smell of each other as soon as you get them apart but in this case, with veterinary intervention necessary, it obviously wasn't possible.
With time and patience, I have managed to re-unite Basenjis after a humdinger of a fight but wouldn't know if the same methods would work on different breeds.