I fairly new to restoring photos and everything I have tried to improve this picture seems to destroy the details in the face or make it look fake. Any tips on how to help this pic would be appreciated. I have used levels and tried curves to enhance the detail with a bit of success but is there any method of cleaning up whats there with out smoothing it out to much?
I have included a piece of the picture where the damage is the worst.

thanks coilte

I'm new at this too and tried my hand at this one. I'd like to compare what I did with what other experienced restorers will do to it. This took about 20 minutes.