What Causes Swollen Legs And Pimple On It?

Dear sir,It s little important. My baby leg is swollen. It has a pimple on it which is slightly burst. If we press the leg, little water oozes out from pimple. Consulted near by Doctor. He said its due to infection. He gave medicines . But we forfeit to ask what foods we can give to him, and what foods to avoid since doctor said infection so. Please help me out.