Chiggers are extremely tiny, and it is very unlikely you will "see" one unless you are looking for them. You will need a hand lens or microscope to see them well. Their presence is best known, instead, by the intensely itchy welts they leave behind, usually where your skin is thin and tender (ankles, backs of knees, about the crotch, under the beltline, and in the armpits) and where tight clothing proves an obstacle to them (as where a belt or elastic band limits their wanderings). (Mosquito bites, by contrast, are usually in exposed places where those flying insects can easily land.) Chigger bites sometimes have a tiny red dot at the center, which is the remains of a scablike tube your body formed in response to the chigger's irritating saliva.
Larval chiggers are red and have 6 legs. A cluster of them can sometimes be seen on your skin because of their reddish color. After a blood meal, chiggers look yellowish. Adult chiggers have 8 legs and look like several other types of mites.