Hi,
I used to have issues with doughnuting below the glans and the occasional lopsided swelling after pumping on my shaft (edema). This can be minimized with proper warm-ups, jelqing, and heat. What I have found to be the most effective is reducing the pressure, keeping it below 10hg, I cycle between 5-10hg for about 15 minutes, 1 minute or so per 1hg up, then the same on the way down. Then clamp for 10-15 mins, then back to the pump. I have serious permanent gains using this method. But it did not happen over night, took about 10 months. Nor was is without discomfort. Over all, I have gained 1 and 1/2, in girth and about a 3/4 inch or so in length. So I went from 6 to 6 3/4" in length and, 5 1/4" in to 6 3/4" or so in girth. Takes commitment too, 5 hours a week and to be honest a lot of discomfort. I plan on stopping at permanent 7 x 7. (Wife will no longer give up the backdoor!) I get as big as 7x7 when pumping/clamping on a daily cycle (edema). But take a week or so off then measure and cycle up again. The only way to tell how big your gains really are. I did take a month off a couple of times, because I was traveling. I saw no shrinkage after the 6 mos mark.
P.S. If you are circumcised like I am, you may grow back your foreskin or at least look like it. Mine now covers about half my glans when soft.