What is the bubble on the scar tissue?

Good QuestionSometimes it is possible to form a blister in response to the surgical adhesive tape. This is rare, and doesn't threaten the final result. The skin will open up, and drain a little bit of fluid. Likely, the superficial skin will come off with the tape. The deep layer of skin will look pink, but will heal up and fade over a couple weeks. Matthew C Camp MD

This type of blister can occur from the shear forces that are put on the skin by the tissues swelling and the tape reaming in place.  It often amounts to nothing serious.

Thank you for your question. The bubble is most likely a blister that has formed and fluid collects under the bubble. This can happen with any sort of tape on the skin. I recommend showing this