My Daughter (10 Years Old) Has A Small Spot On

My daughter (10 years old) has a small spot on her leg that has grown a large swollen area about 10x7mm around. It's very swollen and red. It's also warm to the touch. There are 2 red lines coming from the swollen area about 10mm in length. I just brought her to the doctor who told us it was an infection and gave her antibiotics, stuck it with a needle to drain it but not much came out and swabbed and sent it out. She did not really say anything as far as what it could be or why she was sending it out. Should I be concerned about staph infection?