As shown, a white bump grew on my cat’s paw and the pad is a bit swollen; the yellow next to it is iodine I applied. What is it?

The white bump on your cat’s paw pad is likely a bacterial abscess. Trim the surrounding fur a bit, rinse with saline, and dry with a hairdryer. Then apply iodine daily for disinfection and keep the environment clean; this level of infection usually eases within a few days.

If the abscess grows and the skin thins, use a sterilized needle to pierce and drain it, flush with hydrogen peroxide, then apply some antibiotic ointment to reduce inflammation.