hi i have a question about this power, its says that it doesnt do damage but applies the effect of critical damage, so, what happend with blood loss and lossing the limb?, or what happend if you burn the fate point and get the 10+ effect of critical???

It means that it doesn't actually lower your Wounds total.

but can you lose an arm or a leg like this?

You can't lose a limb from a 3-7 Energy Critical Effect. From the burning a FP effect, it seems like it.