I went on vacation to Belize. I sprayed myself with bug spray and I still got two bite marks right at the top of my socks (ankle area).
At first I felt itchy and saw a quater size red swelling (like a big mosquito bite). In about 2 to 3 hours my ankle became very swollen almost to the size of my fist. I went home and took some Benadryl and the swelling went down and I was able to see the two bite marks (when it was verrrrry swollen you couldn't see any bite marks on the swelling). The two bite marks had a little white pus looking heads. I kept taking benadryl and the swelling kept going down. I later had popped the heads and pus came out.
It is day 5 and my ankle is no longer swollen and the bite marks look much better. They are no longer red. One bite mark has a scab on it and it feels hard when I press on it. There is no pain or itchyness.
Generally bite that affects you that strongly will not be a mystery. The pain from the kind of poison needed to cause a distress like that would make it clear immediately who did the biting. Odds are it was a random innocuous insect bite that carried an infection with it. Check your tempeture, keep a close eye on the leg with the bite. If you're above normal or if there's any swelling or discoloration in the leg go see a doctor. Otherwise it sounds like you're on the mend.