Hi,
There are 2 aspects of management that will help:
First is prevention. Prevention of friction blisters focuses on decreasing friction between the skin and the device. This may be achieved by moisturizing the skin, getting more flexible suction cups, etc.
Second is actual treatment. Treatment of friction blisters focuses on getting the skin to heal quickly without complications. This may be achieved by gently pricking the blister with a sterile needle to drain out the blister fluid to relieve pressure, do NOT deroof the blister as the blister roof will act as a good biological dressing and reducing further trauma to the skin while it heals. Avoid also using an adherent plaster over the blister as it will deroof the blister during removal.
Hope this helps!