Did you find it in the ground? Or in change? I have found buried coins that lose some of the surface features due to corrosion. In fact, I have a 1944 S Mercury dime that looks like it was lost the day it came from the mint, except that the silver has recrystallized from soil chemistry and some of the letters on the reverse near the rim are partly gone. It's a shame when this happens to a really nice coin, but nature takes her toll.