I'm guessing you're talking about the book " Plane Crossing Cultivation ". After the main character Lin Tianyi transmigrated to another plane, he got an ice lion called Little White and a dragon called Big Black as pets. The first time the protagonist met Little White was because Little White was injured and needed the protagonist's treatment and care. I hope my answer is helpful to you. If you like this book, I can recommend other novels of the same genre to you.😉