Though my tenor cuts up the underside of my finger as it has rather sharp fret ends (I'm slowly dulling them with my flesh )You should get some nice callouses out of it. Also it might be the strings and not the frets and if so you could consider switching to a string that's easier on your hands (if you're not using pure nylon already). I'd say just tough it out though.Wow, now I question whether I'm doing something wrong my fingernail is perfectly fine
