Another Hazard in Kettlebell Training

Long fingernails!
Keep em short, otherwise you'll squeeze them right into the flesh of your palm. Not good!

And on the topic of hand care, my two favorite callous tools are:
PedEg. They're at most grocery/drug stores, or online.
Diamancel callous conquerer, also online, and also to be used dry. You need a file to reach the callous under your ring fingers (PedEg won't reach it), and this one works wonderfully. It's heavy-duty, and very long lasting. (I've had mine for several years now).

Many people include corn huskers lotion in their arsenal. I own it, and never use it. Just don't find it necessary. Others swear by it. To each his own. :)

But most importantly, keep your fingernails short, and file your callouses regularly! They WILL get better over time, so just be patient.