Weird Itchy and Painful Rashes. Worried?

I'm noticing these rashes which are linear with small boils, they are increasing day by day despite me not itching or touching them at all. I have 5-6 such rashes on my legs. They are swollen, painful and very itchy and have some black spots in them. They are also very deep red in colour. I consulted a dermatologist for this however she was adamant that this is because I've scratched myself, and gave a TBact cream. But I'm sure that I have not scratched it especially to this extent, I have short nails and I'm very careful, and the rashes are appearing on different spots day by day, one is near the ankle, two on one knee, about 3-4 on another knee and one on inner calf. Does any one know what this is and if I need to be worried?