HUGE blister from mosquito(?) bite

Huge blister from bug bite

36, male, Chinese American, 5'8", 130 lbs. Non smoker, no medications, no health issues.

In Japan now and was checking out temples in a somewhat rural area. Got bitten up pretty good by what I believe are mosquitos (saw them buzzing around, but didn't see them actually bite me). Have about half a dozen bites in addition to what you see in the pic.

As you can see, this blister is HUGE. I do get blisters sometimes from mosquito bites so that's normal, but I have never gotten one half this big before. Aside from the size of it, everything seems normal: there's no pain, it doesn't excessively itch, the skin around it seems fine, doesn't seem infected, color is the same as blisters I've gotten before that healed just fine.

The pic was taken just now, but the bites happened two days ago. I've just been keeping it clean so far and am putting a Band-Aid over it to protect it, but that's about it.

Do I have anything to worry about or should I just leave it alone and let it heal on its own?