You sound like me. My mom says mosquitoes would fly through a blood bank to get to me.
If it
was mosquitoes, they been dinin' on you. And your blood has the stuff they put in it to make it coagulate -- to stop the blood flow once they're done munchin' on us. That's why youre swollen. And it's also probably impeding blood flow.
If the Benadryl doesn't help or the swelling gets worse, you really do need to seek medical attention. Nausea beats dead any day!