Takes much longer to heat than the directions say, and it's very difficult to determine when it is hot enough but not too hot because of the tiny tip. It did a poor job, and trying to clean off the residue that didn't attach to the strip was awful! And as others have said, the redness, swelling, and pain.
The product description did not say it had to be microwaved.
I wish I could find the old Sally Hansen that didn't require heating - that worked the best of all.