I forgot to store the gel strips in the protective cover. Can I still use it?

It depends on where they were and how much UV light they were exposed to. If they have been in daylight or in a sunny place for a long time, it may well be that the gel strips have already begun to harden due to natural UV light. As a result, the durability can be severely impaired, as they can no longer adhere well to the natural nail. In this case, we recommend using a new pack of gel strips.