My 1 year old son has 2 "mosquito"bumps on his arm that now look like a bullseye about 1 inch each. otherwise acting fine. should i be alarmed?

No: Young children have relatively little prior exposure to these insect bites. They often swell and turn red and white. It sill usually resolve spontaneously. Their reactions to insect bites decrease with age and exposure. If there is more redness, the area is tender, or there is fever you should consult with your child's health care provider. There are safe insect repellants and sunscreens for baby.