First off, are you using just your hand for gripping? Having something between your hand and the shaft like maybe a cloth helps the grip and puts somewhat less force on the skin, also you shouldnt be using your glan as the place to grip, it should be your shaft. It’s possible it could be that your growing faster than your skin can replace itself/stretch out, and when that happens it puts more strain on the skin located on the glan.
Actually you could do whatever way you want as long as it’s jelqing, many people here feel that doing different things everytime during a PE session helps, this is mostly known as the Peter Dick Method, basically it means to switch up exercises by either doing a different exercise or changing the amount of time you do it. So if you split up reps and do one type of jelq and then another, I believe this falls under that method.