Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Actually made pain worse!

Canker Covers are a great idea in theory but fall short in practice. Here's why:1. They're too thick. If applied between the lips and the gums, they cause the lips to snag, making it hard to talk or even smile. When wedged between the lips and gum, this thickness puts pressure on the sore.2. They're too dry. Even though they dissolve in time, it still feels like the interface between the canker and the cover is irritatingly dry. Ouch!3. Menthol is an unpleasant sensation. It seems to "perk up" my nerves, which is not a good thing in a wound. I want to numb them!While the covers rid of the periodic, radiating pain of the sores, for me they replaced it with something worse: a steadier, more intense pain.Because of these problems, I've not been able to test the manufacturer's claim that they speed healing.