Depending on the severity of it, i will usually apply calamine to sooth the itchy feeling to prevent my lo from scratching it till it scars. You can diffuse citronella essential oil around the house to prevent mosquitoes
I apply coconut oil. It helps to soothe. I have very sensitive skin. So it usually swells up so bad and can last for a week or two. Coconut oil has been a great help for my family and I.