Staph infection or MRSA?

Over a month ago I had a small blister on my leg that itched, i thought it was a mosquito bite that had become infected from my scratching, it become knotted, red, and raised, I consulted with my doctor and had antibiotics-it was cleared up within a day and a half. After a week I stopped taking my antibiotics (regrettably) because it cleared so fast, now it is a month later and I have since had two other infections so am on antibiotics again and will definately take the full course. I havent had antibiotics since I was about 7 and am now 24, Im wondering, because it has only been 3 boil like infections in over a period of more than a month is it not likely to be mrsa?