#extremely unclear on what this is. possibly different mosquito species are differently immunogenic for me????? but why the delay?

[unopenablebox]

got very mosquito bitten in michigan & most of them were normal and went away fast but a subset (first two on my leg, then one on my left forearm, then two on my right upper arm) swelled up hugely & became very red & intensely itchy and took a very long time to go down & i ended up applying two kinds of anesthetizing cream and icing it to try to manage it a bit even though they didnt really do anything

but im especially perplexed because the two on my right arm didnt show up at all until like. 5 days after we'd come back from michigan? and before that i didnt think i had any bite there at all, and otherwise didn't develop any new bites after i left. so either it's an insanely delayed allergic reaction to only a subcategory of very subtle mosquito bites or i have developed some kind of systemic problem manifesting in slow motion as 2 highly localized welts per week