What Causes Swollen And Red Bump On Inner Thigh?

About a week ago, I found a small bump on my left inner thigh. It became very swollen around the bump and very red. There was eventually a red, tender line leading up to my hip. I went to the doctor and she said it was a bug bite and gave me some antibiotics. The medicine worked and it no longer hurts, or is swollen. But, there is now a rash where all the tender spots were. It almost looks like a hickey or something where the blood has come to the surface of my skin but they are just very tiny dots. The bump is still there but is beginning to go away. Do you know what this rash could be?