Dermatofibroma

I have seen the doctor on in a few occasions about a reddish lump on my leg which I have had for for a good number of years. He seemed to think it was nothing to worry about although over the last 3-4 years I have developed another 3. Looking through the net I think it may be dermatofibromas. How common is this and is it normal to have more than one? I have 4 in total and they are on both legs varying sizes. Since noticing these i have made the mistake of googling it and now regularly worry. Any further info woukd be great! All else failing i will pop back to GP.