i suspect that the main reason this is happening to alot of you is because you are leaving the tape and or adhesive on for too long a period of time. some people say they get 3 weeks hold on tape and glue.. theres alot of bacteria thats gonna build up under that tape from scalp oil, sweat, etc.. ESP in such a long period of time.
i noticed the same thing happened to me once when i left the tape on for 2 weeks straight. i had a nice red line right under where all the tape was.
but it never happens when i keep the tape on for about 7 days and redo it.

to help heal it, like was mentioned put the liquid bandage on so that the tape or glue doesnt touch that area of skin.