Running + hygiene = good results
I find it does make it better, but it doesn't cure it all together. I think the reason it makes it better is not just the increased blood flow as mentioned here but also the impact on insulin levels which is thought to be contributing to acne. In general I find I'm more positive about everything when I run regularly, more energized and my skin appears to be more elastic. Obviously in order to prevent break outs you'd take good care of the hygiene, wash your face and shower asap - and also before workout - that's really important because otherwise if you are wearing your makeup or heavy creams or generally if you last washed your face in the morning and you're running in the evening, with all the sebum and dust/dirt from the environment it will clog more easily as you sweat while working out. It's also important to enjoy what you're doing, even if not 5 out of 5 times. I know many try once or twice and quit because they see it as a struggle. It's not too motivating then. Those weirdos runners - the sub-species. They're not - some find freedom in running, some like challenging themselves, others love the ever-changing views as they run. If you tried and did not quite like it - don't just quit thinking it's not for you. Try and make it a pleasant experience. And physically it also gets much easier as you follow through. Good luck!