What is the difference between flea bites and bedbug bites?

I have only a few small red bites on my foot/ankle area that itch, but not too bad. One of them itched really bad so I used my sock to scratch it thinking it would be better than scratching with my fingernails. After I scratched it the spot became instantly bigger and very bright red around the boarder and slightly lighter in the center. There is no redness around any other part of it. It is leaking fluid, I saw this on my sock and the band-aid. It gets redder daily, but does not itch anymore. I am not getting any more bites at all. I was outside, on my wooden stairwell of my apartments. We live in an area where sand is common, even in the soil. I have had flea bites before and none of them ever looked like the big bite I have, but they looked just like the other bites. Like I said it looks close to a cigarette burn, but that isn't what it is. My neighbor had her apartment treated for bedbugs, and I was standing close to her front door, but so were my husband, two children, a friend of my child's, and two other neighbors of ours. None of them have the bites.