Small blisters on skin after hanging

I am uncircumcised and I pull the skin around the glans and tape the glans. After hanging I saw a few very small blisters on the skin and none on the glans where I tape. Do I must tape the skin too? Am I hanging for too much? I started with the minimum weight for 20 minutes and saw the blisters at around 45 minutes per session (I do 3 sessions per day when I train)

You could try a smaller vacuum cup. Thats what I do. I don’t tape, but use a vacuum cup that is smaller than my erect glans size. Probably not advisable to do as I do, but this method does limit the damage I could possibly. Your total time each day is longer than I do as well though. I do 50 minutes heated, then 10 minutes cool down under tension

On second note, I pull my foreskin all the way back before installing the vacuum cup to avoid Turkey neck/pulling the nut sack out onto the shaft.