Maintain Calluses to Prevent Pain and Rips!

Bar hurting your hand? Hands getting ripped apart? You need to maintain your calluses! The best way I've found to do this is to just have a pumice stone (even the 99 cent store sells these, it's just a porous volcanic rock) and at the end of a hot shower, you rub the stone on your callus until it's smoothly contoured evenly with the surrounding skin. (A callus doesn't need to be thick for it to provide protection. Calloused skin is still strong even if it's not overgrown. It's thousands of compressed layers of dead skin due to pressure.) Also, at the end of the hot shower, if you see white skin, that can generally rubbed off as well. That's basic maintenance that works pretty well. Some people use razors and stuff but the stone works much more evenly in my experience.
If you've already ripped and want the rip to heal faster, put Neosporin on it (or any generic triple antibiotic ointment) the first night (to ensure you don't get an infection) and then on the subsequent nights, put lotion on them to keep the skin moisturized while you sleep at night. If you want it to work even better, moisturize your hands and put a big sock over your hands when you go to sleep and it will stay super warm/moist all night and you'll wake up to see noticeably more skin growth, especially if you live in a normally dry/cold environment.
If you ripped and must absolutely train again for whatever reason, simply putting a bandage and wrapping it with athletic/sports tape might help to reduce the pain. Or some people use krazy glue. It stings, but it works if you're desperate.