How to treat mites on cats:
1. First, the cats should be isolated to prevent them from infecting each other.
2. Trim the fur around the affected area of the cat, wash the affected area with warm water, and then spray it with an anti-mite agent.
3. Put an Elizabethan collar on the cat to prevent it from licking its wound.
4. If the mites on the cat are very severe, even visible all over the body, a full-body medicated bath can be given. However, many people are not good at administering medication and performing the procedure, so it is recommended to take the cat to the vet for treatment.
5. During a cat's illness, keep the environment clean and tidy, let the cat live in a well-ventilated place, supplement the cat's nutrition, and enhance its immunity. 
Reasons why cats get mites:
1. Poor living environment: Cats living in damp, bacteria-infested environments are more likely to get mites.
2. Nutritional deficiencies in cats, as well as low resistance and immunity, can also lead to mites in cats.