You can blister in five minutes. It’s not the time that causes blistering. It’s high or over pressure. You can’t speed up breast growth. Swelling isn’t growth. It takes time for anything to grow. But, the longer you can keep your breast enlarged or swelled, it helps keep blood vessels engorged with blood which hopefully aids in cell growth. It does not grow in a matter of a month, but many months or even years. I highly suggest, speaking from experience, do not use creams or lotions as lubricant in conjunction with pumping. Use oil. Lotions dry or soak in to quickly and you lose lubrication or “slipperiness” in the cup and now your skin sticks. Having your boob slide in the cup will aid in filling the cup. Again, experience of many years, trying many ways has brought me to that conclusion. Be generous with the oil. After pumping massage it all in. If you do get some blisters, when you remove your cups massage them smooth. You can still pump, but back it down a few days but keep them pumped. Here again, over pressurizing can be your enemy. Pump as often as you can, 15 minutes a time is enough but do it as many times a day as you can. Keep them pumped up. Keep the blood flowing to them. Mine are still increasing. I’m still amazed after all these years that I have my “own”!! One last thing, find what regimen works for your schedule and stick to it.