The development of calluses varies for each individual, but generally, it can take several weeks to a few months of regular practice to form calluses. These hardened layers of skin on your fingertips will help you play guitar more comfortably and reduce the chance of injury. Remember to be patient and consistent in your practice routine for the best results. You might notice when you start to play lead guitar that given you will be bending strings that your fingers may be more sore than usual - this is totally normal. As with general chord playing and holding down notes, your fingers will get used to this. If the pain persists consider trying lighter strings i.e. no more than gauge 10 (Top E string) this will ease the pain on those bends.