if the chip doesn't die, it will probably not function properly. i've had this problem before when hooking a 5v uc to a 3.3v FPGA. it didn't damage either, but some weird stuff happened. i don't know how the PIC will handle being overloaded, but i wouldn't try to find out.
if you need more current than the PIC can provide, then you should look into adding some sort of transistor switching circuit to your outputs.