I think the hardest thing about learning to bend really well is keeping those other strings from sounding or causing physical pain!
When you bend towards the bass strings other other strings can get caught high up on the tips of your fingers digging in under the nail where there isn't much of a callous. I recommend keeping your finger nails really short (so the other strings don't get caught under) not using the very tip of your fingers for such a bend but using positioning your fingers a little flatter so that the tip of the finger (and not the underside of your nail)is pushing the other strings away.
Bending towards the treble strings you won't be liable to catch the string under your nail, when I bend like this the tip of my finger rotates a little and some of the bending force comes not from the finger but from the rotation of the wrist as the basal joint of the first finger catches against the neck - like the so called "butterfly vibrato".
If you want to toughen your finger tips try brushing them with surgical spirits, I know that walkers do the same to toughen their feet.