I have itching & water blisters along the edges of the Tegaderm applied after surgery. How can I prevent/treat blisters? (Photo)

These water blisters are very itchy and once they pop, they somewhat scab over. Funny thing is they are only along the edges of the Tegaderm and mostly in my cleavage and the medial aspect of my breasts. I've cut the Tegaderm back but new blisters form at the borders. I've used Benadryl pills and cream and Aquafor which stops the itch but new blisters still form. PS says there is no infection. What are these blisters and how can I prevent more from forming as I don't want to risk an infection?