Non-prescription creams containing hydrocortisone or antihistamines (like Benadryl) are useful. A paste made of baking soda and water which is applied to the affected area is an often-used home remedy.
Your child could have gotten an infection from the mosquitoes. It's also possible he could be allergic to them. You should take him to a doctor right away. If his throat starts to close up take him to the Emergency Room.
Calamine lotion works to keep the itching down. You should also then try to keep them from itching them and picking at them to keep them from scabbing and scarring.
Hai, Mosquito bites are not a serious problem, but some times it may cause health problems. The hard welts after getting mosquito bites are cured with in 1 week.