What is this?

So on Sunday I got really icky on my back in the area you see in the pictures and I checked and I saw these red bumps and I wasn’t itching them like crazy as I would with a mosquito bite, Monday too the one on my arm was itchy but only a little and today Tuesday I check them and they’re completely flat and blotchy and idk what it is lol are they bed bug bites or hives idk help and I only have them in that one spot no where else does anyone know????