I used all purpose instead of self rising flour and my cobbler is done. Will it taste terrible?

Without baking powder, it's going to be like a rock IMO. I agree with SusanW, use the filling and make it into something else, I'd say a crisp would be very easy.

I agree with Susan, it is supposed to be cakey. I would taste a piece of the "cake" part to see if it is to hard. Good Luck

Personally, I would think the "cake" part of it will be similar to cement with no leavening. The only way to know for sure is to taste it. I wouldn't serve it to others without trying it. If it isn't up to snuff, could you scoop out the fruit and use it as a sort of compote over purchased or homemade angel food cake, pound cake, biscuits or even just over some excellent vanilla ice cream? This may be a time for repurposing.

Don't worry -- the texture might be a little bit dense, but it should taste just as delicious!