Signs of a skin infection include:
A sunburn may make your skin feel dry and itchy. Any scratching might cause an open skin sore. A sunburn can also cause skin blisters that can break open and leave an open skin sore, which can become infected. Home treatment may be all that is needed.
Infection is more likely to develop if open blisters are present. It is important to try to keep children from scratching a sunburn so they do not get open skin sores that might become infected.
WebMD Medical Reference from Healthwise