Well, if it smells like KFC (or the silicon equivalent), the bad news is there's nothing you can do.
If its just bent pins, just unbend them, and it works like a charm.
If it got wet, just let it dry for a couple of weeks, it should work.
If you forgot to put the heatsink on, and weird smoke starting coming out, like a genie was trying to get out of the CPU, bad news. The genie doesn't do wishes, and he wants you to buy a new CPU.
Same if you put too many volts in, irrespective of the smoke.