Can a toddler get petechiae on his neck from a car seat strap that is too tight?

Petechiae: It can occur from tight seat belt in the area of direct pressure. There are different causes of petechiae including infections/malignancy. Petechiae seen on face from forceful vomiting/ severe coughing

Sure: Toddlers can get peteciae anywhere above the heart level from simple things like a harsh cough, vomiting or a tight strap.The issue is cosmetic and not of any medical significance.Better to be strapped in tight than to fly out of the car in a crash.