[t1m]

You shouldn't peel your callous off because you may do even more damage to it by doing so. Instead, take nail clippers and clip off the part hanging off and if needed, sand down the edges with a fine grit nail board.

In the future, you should stop playing after you notice your callouses first start cracking, peeling, or splitting. Rub some lotion on them and call it a day (or come back in a few hours.) At first, it may only be a few minutes before you have to take a break, however, if you keep doing this, your callous will become very tough and resilient over time. I've been using this method for about 2 years now and have gotten to the point where I can play 6+ hours without my callouses cracking, peeling, or splitting.