Hi scmom~
Welcome!
My 3 y/o daughter is a little allergic to mosquito bites and she gets these welts all over her. Unfortuately, it is almost impossible to avoid being in the mosquitos where we live! I like to give a little oral benadryl to keep her from scratching. I also like to put some Benadryl ointment on and put a bandaid. If not, she will scratch and dig at it until it causes scabs.
For prevention, I like the Avon Skin-So-Soft sunscreen/insect repellent. It repels mosquitos, fleas and ticks.It says on the back that it is ok for children over 6m (younger need to check with dr). I really like it because it works well, includes sunscreen and it comes in different scents. I think they even have one now that is blue when you apply it so you can see where you missed. Hope something helps!