each time after a mosquitoe bit, the erae get sowlen, why? what can be the local treatement

Some people are allergic to the toxin that mosquitoes inject in the human body while they are drinking blood.

Hi! Yes, a serious reaction to mosquito bites might occur, which results in swelling. This swelling may also happen in throat so you should take it seriously and talk to your doctor. Till then avoid areas infested by mosquitoes and use mosquito-repellent on exposed skin.