If bitten when sitting outside...Mosquitos or Gnats. (Yes, we do have Mossies...just that they don't carry Malaria, Dengue,etc).

If inside...FLEAS. Normally the cat flea that bites humans.

Bed bugs tend to leave larger red marks, but could be.

Ticks are also common in summer, and can be picked up from animals or just walking through vegetation.

If very itchy and between fingers or other sweaty places...could be Scabies, which you'd need to go to a Doctor about, and he'd send you to the Skin Clinic, which might be a good idea anyway if these 'bite' marks aren't
going away.

Changing carpets, furniture, bedding etc won't get rid of fleas, bedbugs, lice, because they hide and lay their eggs in crevices in the floor, door and window frames. The affected rooms need to be fumigated.