I actually get string grooves across my callouses which remain hours after I stop playing.
Your callouses are your friends. Take care of them. That includes using an emory board or light-grit sandpaper to smooth off the rough bits from time to time, otherwise they will catch on your strings or will peel too much and you'll be tempted to pull or cut them off. (Don't do that or you'll hurt like a newbie all over again.)
Use moisturizer on your fingertips before you go to sleep. Your fingers should regain some normal shape by the time you wake up, but will still be as hard as little hammers. That's a good thing.
"Just because you've always done it that way doesn't mean it's not incredibly stupid." - Despair, Inc.