Yesterday, I started to take the contraceptive pill Alysena28 to regularize my cycle. Today is my second day and I escaped the pill and I can no longer find it. Is it serious if I jump my second day?

The 21 pills in your Alysena box have the same hormone content. If today is your 2nd day, I suggest you take another pill (either tomorrow's or the 21st) to continue taking it for the next few days. If you want additional contraceptive protection in addition to regularizing your cycle, you should renew your next pack earlier to make sure you have had at least 21 days of medication and a maximum of 7 days without hormones. If contraception is not an issue, you can simply start your next box a few days earlier.