The causes of red, swollen and hard skin are mainly mosquito bites, allergies, infections, etc. Before treatment, you need to improve the relevant examinations to clarify the causes and then symptomatic treatment. Treatment methods include medication. 1. If it is caused by mosquito bites, you can usually observe it first, and it can usually return to normal within a period of time. If the itching is severe, you can use mometasone furoate cream to help relieve it. 2. If it is caused by allergy, anti-allergy medication can be administered, such as loratadine tablets and cetirizine tablets. 3. If the skin is red, swollen and hard due to infection, symptomatic treatment is usually needed depending on the degree of infection. If the infection is mild, you can use ichthyol ointment, mupirocin ointment and other drugs. If the infection is more severe, antibacterial medications such as oral cefaclor will be needed. The causes of skin redness, swelling and hard lumps are different, and the treatment methods will also be different, so it is necessary to consult a doctor in time, under the advice of the doctor for scientific treatment. All the above medicines should be used as prescribed by the doctor.